Implantable electrode location selection

ABSTRACT

Systems, methods, and interfaces are described herein for assisting in noninvasive location selection for an implantable electrode for use in cardiac therapy. Mechanical motion information and surrogate electrical activation times may be used to identify one or more candidate site regions.

The disclosure herein relates to systems, methods, and interfaces forimplantable electrode location selection.

Implantable electrodes may be used in various systems, apparatus, andmethods for medical treatment of a patient. More specifically,implantable electrodes may be located adjacent, or in contact, withtissue (e.g., cardiac tissue, etc.) of a patient to deliver therapy tothe tissue of the patient and/or sense signals from the tissue of thepatient. Some electrodes may be more effective, or optimal, atdelivering therapy than others (e.g., due to location, contact, etc.).

Various pacing therapies (e.g., cardiac resynchronization therapy) maydeliver electrical pacing to the left ventricle of a patient's heart.Implantable electrodes used to deliver left ventricular pacing may belocated in one or more branches of the coronary sinus proximate thepatient's left ventricle. Different implantation site regions (e.g.,locations within the one or more branches) of the coronary sinus may bemore effective, or optimal, than others in delivering pacing therapy.

SUMMARY

The exemplary systems, methods, and interfaces described herein may beconfigured to assistance a user (e.g., a physician) in the locationselection for one or more implantable electrodes for use in deliveringcardiac therapy to a patient. The systems, methods, and interfaces maybe described as being non-invasive. For example, the systems, methods,and interfaces may not use implantable devices such as leads, probes,catheters, etc. to assist the user in the location selection for one ormore implantable electrodes. Further, for example, the systems, methods,and interfaces may not relate to feedback from what occurs during pacingfrom a given location of an implanted electrode. In other words, theexemplary systems, methods, and interfaces may be directed to selectingan optimal implantable electrode position before the implanted electrodeis implanted, or put into, a patient from electrical and/or mechanicalmeasurements taken noninvasively.

More specifically, the exemplary systems, methods, and interfaces mayuse mechanical motion data in combination with surrogate electricalactivation data to identify one or more candidate and/or target implantsite regions for the implantable electrodes. The mechanical motion datamay be measured using imaging apparatus configured to image at least aportion of a patient's heart (e.g., a portion of the heart's bloodvessel anatomy). The surrogate electrical activation data may bemeasured using one or more external electrodes (e.g., external to apatient's body) located adjacent a patient's skin. In at least oneembodiment, the surrogate electrical activation data may be noninvasiveestimations of local activation times (e.g., q-LV times) of regions of apatient's heart taken along the short-axis of the heart (e.g.,electrical activation times may not vary much across the long-axis ofthe heart).

Additionally, one or more graphical user interfaces may displaymechanical motion information and/or surrogate electrical activationinformation of a patient to, e.g., assist a user in the selection oflocations for one or more implantable electrodes, and subsequently,navigating the one or more implantable electrodes to such locations. Theexemplary systems, methods, and interfaces may be described as a tool toprovide additional information to a user to aid in the locationselection for implantable electrodes and/or an automated recommendationengine to identify locations for one or more implantable electrodes.

One exemplary system for assisting in noninvasive location selection foran implantable electrode may include electrode apparatus, imagingapparatus, display apparatus, and computing apparatus coupled to theelectrode apparatus, imaging apparatus, and display apparatus. Theelectrode apparatus may include a plurality of external electrodesconfigured to be located proximate tissue of a patient (e.g., surfaceelectrodes positioned in an array configured to be located proximate theskin of the patient). The imaging apparatus may be configured to imageat least a portion of blood vessel anatomy of the patient's heart (e.g.,at least a portion of the coronary sinus). The display apparatus mayinclude a graphical user interface configured to depict the at least aportion of blood vessel anatomy of the patient's heart (e.g., the atleast a portion of blood vessel anatomy of the patient's heart displayedon the graphical user interface is a three-dimensional graphicalrepresentation). The computing apparatus may be configured to providethe graphical user interface displayed on the display apparatus toassist a user in noninvasively selecting a location for an implantableelectrode (e.g., at least one implantable electrode coupled to at leastone lead). The computing apparatus may be further configured to display,on the graphical user interface, at least a portion of blood vesselanatomy of the patient's heart, measure mechanical motion of the atleast a portion of blood vessel anatomy of the patient's heart using theimaging apparatus, display, on the graphical user interface, mechanicalmotion information of one or more regions of the at least a portion ofblood vessel anatomy of the patient's heart based on the measuredmechanical motion (e.g., color scale the at least a portion of bloodvessel anatomy of the patient's heart on the graphical user interfaceaccording to the measured mechanical motion). The computing apparatusmay be further configured to identify a region of the one or moreregions of the at least a portion of blood vessel anatomy of thepatient's heart, measure surrogate electrical activation time using oneor more external electrodes of the plurality of external electrodes ofthe electrode apparatus proximate the identified region of the at leasta portion of blood vessel anatomy of the patient's heart, and display,on the graphical user interface, the measured surrogate activation timefor the identified region of the at least a portion of blood vesselanatomy of the patient's heart (e.g., alphanumerically depict themeasured surrogate activation time proximate the identified region ofthe one or more regions of the at least a portion of blood vesselanatomy of the patient's heart on the graphical user interface).

One exemplary method for assisting in noninvasive location selection foran implantable electrode may include displaying on a graphical userinterface at least a portion of blood vessel anatomy of a patient'sheart (e.g., at least a portion of the coronary sinus, athree-dimensional graphical representation, etc.), measuring mechanicalmotion of the at least a portion of blood vessel anatomy of thepatient's heart using imaging apparatus, and displaying on the graphicaluser interface mechanical motion information of one or more regions ofthe at least a portion of blood vessel anatomy of the patient's heartbased on the measured mechanical motion (e.g., color scale the at leasta portion of blood vessel anatomy of the patient's heart on thegraphical user interface according to the measured mechanical motion).The exemplary method may further include identifying a region of the oneor more regions of the at least a portion of blood vessel anatomy of thepatient's heart, and measuring surrogate electrical activation timeusing one or more external electrodes proximate the identified region ofthe one or more regions of the at least a portion of blood vesselanatomy of the patient's heart. The one or more external electrodes maybe located proximate tissue of a patient (e.g., surface electrodespositioned in an array configured to be located proximate the skin ofthe patient). The exemplary method may further include displaying on thegraphical user interface the measured surrogate activation time for theidentified region of the one or more regions of the at least a portionof blood vessel anatomy of the patient's heart (e.g., alphanumericallydepict the measured surrogate activation time proximate the identifiedregion of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart on the graphical user interface)and navigating at least one implantable electrode (e.g., at least oneimplantable electrode coupled to at least one lead) to the identifiedregion of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart using the graphical userinterface.

In one or more exemplary systems and/or methods, measuring surrogateelectrical activation time using one or more external electrodes of theplurality of external electrodes of the electrode apparatus proximatethe identified region of the at least a portion of blood vessel anatomyof the patient's heart may include identifying positions of theplurality of external electrodes with respect to the identified regionof the at least a portion of blood vessel anatomy of the patient's heartusing the imaging apparatus and measuring surrogate electricalactivation time using the one or more external electrodes of theplurality of external electrodes of the electrode apparatus that areclosest to the identified region of the at least a portion of bloodvessel anatomy of the patient's heart. In at least one embodiment,graphical representations of positions associated with the plurality ofexternal electrodes with respect to the at least a portion of bloodvessel anatomy of the patient's heart may be displayed on the graphicaluser interface.

In one or more exemplary systems and/or methods, the plurality ofexternal electrodes may be configured to be positioned proximate tissueof the patient by a user. Each external electrode of the plurality ofexternal electrodes may be positionable proximate a different specificarea of the patient than the other external electrodes of the pluralityof external electrodes, and each different specific area may correspondto a different region of the patient's heart. Further, measuringsurrogate electrical activation time using one or more externalelectrodes of the plurality of external electrodes of the electrodeapparatus proximate the identified region of the at least a portion ofblood vessel anatomy of the patient's heart may include measuringsurrogate electrical activation time using the one or more externalelectrodes of the plurality of electrodes of the electrode apparatusthat correspond to the identified region of the at least a portion ofblood vessel anatomy of the patient's heart.

In one or more exemplary systems and/or methods, identifying a region ofthe one or more regions of the at least a portion of blood vesselanatomy of the patient's heart may include allowing a user to select theregion of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart using the graphical userinterface.

In one or more exemplary systems and/or methods, the computing apparatusmay be further configured to execute and the method may further includedisplaying, on the graphical user interface, scar information for theidentified region of the one or more regions of the at least a portionof blood vessel anatomy of the patient's heart indicating a likelihoodof the identified region including scar tissue.

One exemplary system for assisting in noninvasive location selection foran implantable electrode may include display apparatus and computingapparatus coupled to the display apparatus. The display apparatus mayinclude a graphical user interface configured to depict at least aportion of blood vessel anatomy of the patient's heart. The computingapparatus may be configured to provide the graphical user interfacedisplayed on the display apparatus to assist a user in noninvasivelyselecting a location for an implantable electrode. The computingapparatus may be further configured to display, on the graphical userinterface, at least a portion of blood vessel anatomy of the patient'sheart, display, on the graphical user interface, mechanical motioninformation of one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart, and display, on the graphicaluser interface, a measured surrogate activation time for an identifiedregion of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart.

One exemplary method for assisting in noninvasive location selection foran implantable electrode may include displaying on a graphical userinterface at least a portion of blood vessel anatomy of a patient'sheart, displaying on the graphical user interface mechanical motioninformation of one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart, and displaying on the graphicaluser interface a measured surrogate activation time for an identifiedregion of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart.

One exemplary noninvasive method may include identifying areas of lateelectrical activation based on surface ECG leads in a proprietary‘belt-like’ configuration. Sequence of ventricular activation duringintrinsic rhythm and/or right ventricular pacing may be derived fromthis belt. Regions of the late left ventricle activation can bedetermined from the derived sequence. The data can be used inconjunction with data derived from mechanical motion of theleft-ventricle (e.g., motion maps) to pre-select optimal area forplacement of a left ventricular lead.

One exemplary embodiment uses the ventricular activation sequence asmapped from surface electrodes to pre-select an optimal location of aleft ventricular lead in conjunction with other methods (e.g., motionmaps) of looking at mechanical motion of the left ventricle. Activationdata from external electrode leads may be mapped to certain grossregions of the left ventricle. For example, activation from leftanterior electrodes may be mapped to the anterior left ventricle,activation from left-lateral electrodes may be mapped to the lateralwall of the ventricle, activation from posterolateral electrodes may bemapped to a posterolateral location of the left ventricle, andactivation from left posterior electrodes may be mapped to a posteriorlocation of the left ventricle.

A preliminary target location may be selected based on the latest areaof contraction from the motion map, and electrical activation times fromthe external electrodes corresponding to that particular area may bechosen. The activation time-data from electrodes corresponding to aparticular anatomic area may be averaged to represent the activationtime over that particular region. If the activation data indicates earlyactivation, e.g., if the activation time is less than a certain value(e.g., a value which can be about 80 milliseconds to about 100milliseconds) as measured from onset of depolarization or if theactivation time is less than a certain percentile of the latestactivation recorded from the external electrodes (e.g., where thispercentile can be any value from about 50% to about 75%), then thatlocation may be ruled out as an optimal site (e.g., because of earlyactivation-times). If the external electrode activation data indicateslate activation in that area (e.g., the data does not satisfy thecriteria of early activation described above) and the externalelectrodes situated in the corresponding anatomic area do not show signsof a local scar (e.g., including fractionations (multiple deflections),small q-waves at the onset followed by r-waves, where q/r ratio isbetween 20-30%, or signs of ST segment elevation), the preliminarytarget location may be selected for implanting the implantable electrodeand/or lead. The signs of scarring described here may be oftenclinically used for diagnosing myocardial infarction and may beinspected visually as well. The activation map from surface electrodesas well as the motion map over at least one cardiac cycle correspondingto the preliminary target area may be displayed.

One exemplary method may combine data from electromechanical mapping anda likelihood score for scar to select an optimal site for implantableelectrode and/or lead placement. The data for combination may includetiming of mechanical contraction of different regions of the targetventricle, e.g., left ventricle, as determined from a motion map, motioncurves and features of the motion curves (e.g., peak-amplitudes ofmotion curves in the different regions of the target ventricle),electrical activation data in different regions of the left ventricle,and electrical signals, e.g., surface electrocardiogram signals, fromsurface electrodes in close proximity to different regions of the leftventricle. The exemplary method may combine all these different piecesof information to come up with a recommendation of an optimal targetsite.

For example, a subset of possible candidate regions may be identifiedbased on certain thresholds of electrical activation times andmechanical contraction times. Regions that are activating electricallylater than a certain percentage of the latest electrical activation timeamong all target regions and mechanically contracting later than acertain percentage of the latest mechanical contraction times amongstall target regions may be chosen as potential candidate sites for leadplacement. The certain percentages may be between about 70% and about100%. Next, for example, each region from this subset may be assigned ascar risk score of 0-2 based on the one or more criteria and processes.For example, initially, all regions may be assigned a scar risk score of0 and the following criteria are evaluated: peak-to-peak amplitude of amotion curve corresponding to a region being less than a selectedpercentage (e.g., 0% to about 50% such as 10%) of max peak-to-peakamplitude among all target regions may add 1 to the scar risk score forthat region. Electrical signals (e.g., surface electrocardiogramelectrodes) at or in proximity to the region showing one or more signsof scarring that includes ST segment elevation, fractionations, lowpeak-to-peak amplitudes (e.g., <1 mV) may add 1 to the scar risk scorefor that region. Once evaluation for scar risk scores is completed, thecandidate regions may be sorted in descending order of scar risk score.The region with the lowest scar risk score may be selected as the finalsite for the lead. If all sites are at the highest scar risk score(e.g., 2), then new candidate sites may be selected by lowering each ofthe thresholds by a selected amount (e.g., about 10% to about 20%). Forexample if initial selected percentages were 75% each, new, loweredpercentages may be 65%. In one embodiment, instead of using percentilethresholds, absolute thresholds may be used for one or more of thevariables of interest (e.g., electrical activation times greater than orequal to a selected value between about 50 milliseconds and about 150milliseconds).

One exemplary method may include identifying a candidate site for leftventricular (LV) lead implant on a 3-D model of cardiac sinus (CS)venous anatomy, reconstructing body-surface markers and finding themarker in closest proximity of the candidate site, determining surfaceelectrocardiogram (ECG) electrodes (e.g., unipolar electrodes) inclosest proximity to the marker previously found, and display anestimate, or surrogate, of electrical activation time (e.g., q-LV time)on a display module (e.g. monitor/screen, etc.) integrated with the 3Dmodel/motion map. Further, the local electrical activation time (e.g.,the q-LV time) may be estimated from the estimated, or surrogate,activation time determined from the ECG signals from surface electrodesidentified previously.

One exemplary method may include determining mechanical contractiontimes at target sites during baseline rhythm (e.g., from motion map dataof the target veins), determine electrical activation times in targetsites during baseline rhythm via surrogate electrical activation times(e.g., q-LV times) acquired from a surface electrocardiogram (ECG) belt,identifying candidate sites from among mapped sites which are within athreshold (e.g., 75%) of the latest mechanical contraction and within agiven threshold (e.g. 75%) of the latest electrical activation time,evaluating scar risk score from motion/strain curves and surface ECGsignals for each of the candidate sites, and/or identifying optimalsites as the candidate sites with the lowest scar risk score.

The above summary is not intended to describe each embodiment or everyimplementation of the present disclosure. A more complete understandingwill become apparent and appreciated by referring to the followingdetailed description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary system including electrodeapparatus, imaging apparatus, display apparatus, and computingapparatus.

FIG. 2 is an exemplary graphical user interface depicting mechanicalmotion information of a portion of a patient's heart.

FIGS. 3A-3B are diagrams of exemplary external electrode apparatus formeasuring torso-surface potentials.

FIG. 4 is a diagram of exemplary surface locations of a patient mappedto implantation site regions of the patient's heart.

FIG. 5 is a diagram depicting late surrogate activation time in theposterolateral surface location of a patient measured using externalelectrodes.

FIG. 6 is a diagram depicting locations of external markers associatedwith one or more external electrodes.

FIG. 7 is an exemplary graphical user interface depicting blood vesselanatomy, mechanical motion information thereof, and locations of theexternal markers of FIG. 6.

FIG. 8 is a block diagram of an exemplary method of assisting innoninvasive location selection for an implantable electrode.

FIGS. 9A-9B are exemplary graphical user interfaces depicting bloodvessel anatomy configured to allow a user to select an implantation siteregion of a patient's heart.

FIG. 10 is an exemplary graphical user interface depicting a region of apatient's heart including blood vessel anatomy, mechanical motioninformation and surrogate electrical activation information.

FIG. 11 is a block diagram of another exemplary method of assisting innoninvasive location selection for an implantable electrode.

FIG. 12 is a block diagram of an exemplary method of noninvasivelydetermining scar risk for an implantable site region of a patient'sheart.

FIG. 13 shows graphs of mechanical motion information for four differentimplantable site regions of a patient's heart.

FIG. 14 shows graphs of surrogate electrical information for the fourdifferent implantable site regions of the patient's heart of FIG. 13.

FIG. 15 is a diagram of an exemplary system including an exemplaryimplantable medical device (IMD).

FIG. 16A is a diagram of the exemplary IMD of FIG. 15.

FIG. 16B is a diagram of an enlarged view of a distal end of theelectrical lead disposed in the left ventricle of FIG. 16A.

FIG. 17A is a block diagram of an exemplary IMD, e.g., the IMD of FIGS.15-16.

FIG. 17B is another block diagram of an exemplary IMD (e.g., animplantable pulse generator) circuitry and associated leads employed inthe system of FIGS. 15-16 for providing three sensing channels andcorresponding pacing channels.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following detailed description of illustrative embodiments,reference is made to the accompanying figures of the drawing which forma part hereof, and in which are shown, by way of illustration, specificembodiments which may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from (e.g., still falling within) the scope of the disclosurepresented hereby.

Exemplary systems, apparatus, and methods shall be described withreference to FIGS. 1-17. It will be apparent to one skilled in the artthat elements or processes from one embodiment may be used incombination with elements or processes of the other embodiments, andthat the possible embodiments of such methods, apparatus, and systemsusing combinations of features set forth herein is not limited to thespecific embodiments shown in the Figures and/or described herein.Further, it will be recognized that the embodiments described herein mayinclude many elements that are not necessarily shown to scale. Stillfurther, it will be recognized that timing of the processes and the sizeand shape of various elements herein may be modified but still fallwithin the scope of the present disclosure, although certain timings,one or more shapes and/or sizes, or types of elements, may beadvantageous over others.

From unipolar electrocardiogram (ECG) recordings, electrical activationtimes can be detected or estimated in proximity of a reference location(e.g., which can be a chosen location for the left ventricle lead duringimplant). Such electrical activation times may be measured anddisplayed, or conveyed, to an implanter by a system which acquires theECG signals and generates the metric of electrical activation (e.g.,q-LV) time. As described herein, at least in one or more embodiments,electromechanical mapping to select a lead placement site for cardiacresynchronization therapy may use an algorithm that uses q-LV data(e.g., electrical activation times) in conjunction with mechanicalmotion map timings to best select a site for a LV lead. For example,such an algorithm may provide an optimizing scheme that takes intoaccount electrical and mechanical times as well as any information aboutscar tissue that can be derived from ECG/motion profile/curvemeasurements.

As described herein, various exemplary systems, methods, and interfacesmay be configured to use electrode apparatus including externalelectrodes, imaging apparatus, display apparatus, and computingapparatus to noninvasively assist a user (e.g., a physician) inselecting one or more locations (e.g., implantation site regions)proximate a patient's heart for one or more implantable electrodesand/or to navigate one or more implantable electrodes to the selectedlocation(s). An exemplary system 100 including electrode apparatus 110,imaging apparatus 120, display apparatus 130, and computing apparatus140 is depicted in FIG. 1.

The electrode apparatus 110 as shown includes a plurality of electrodesincorporated, or included within a band wrapped around the chest, ortorso, of a patient 14. The electrode apparatus 110 is operativelycoupled to the computing apparatus 140 (e.g., through one or wiredelectrical connections, wirelessly, etc.) to provide electrical signalsfrom each of the electrodes to the computing apparatus 140 for analysis.Exemplary electrode apparatus 110 will be described in more detail inreference to FIGS. 3A-3B.

The imaging apparatus 120 may be any type of imaging apparatusconfigured to image, or provide images of, at least a portion of thepatient in a non-invasive manner. For example, the imaging apparatus 120may not use any components or parts that may be located within thepatient to provide images of at least a portion of the patient exceptnon-invasive tools such as contrast solution. It is to be understoodthat the exemplary systems, methods, and interfaces described herein maynoninvasively assist a user (e.g., a physician) in selecting a locationproximate a patient's heart for an implantable electrode, and after theexemplary systems, methods, and interfaces have provided noninvasiveassistance, the exemplary systems, methods, and interfaces may thenprovide assistance to implant, or navigate, an implantable electrodeinto the patient, e.g., proximate the patient's heart.

For example, after the exemplary systems, methods, and interfaces haveprovided noninvasive assistance, the exemplary systems, methods, andinterfaces may then provide image guided navigation that may be used tonavigate leads including electrodes, leadless electrodes, wirelesselectrodes, catheters, etc., within the patient's body. Further,although the exemplary systems, methods, and interfaces are describedherein with reference to a patient's heart, it is to be understood thatthe exemplary systems, methods, and interfaces may be applicable to anyother portion of the patient's body.

The imaging apparatus 120 may be configured to capture, or take, x-rayimages (e.g., two dimensional x-ray images, three dimensional x-rayimages, etc.) of the patient 14. The imaging apparatus 120 may beoperatively coupled (e.g., through one or wired electrical connections,wirelessly, etc.) to the computing apparatus 140 such that the imagescaptured by the imaging apparatus 120 may be transmitted to thecomputing apparatus 140. Further, the computing apparatus 140 may beconfigured to control the imaging apparatus 120 to, e.g., configure theimaging apparatus 120 to capture images, change one or more settings ofthe imaging apparatus 120, etc.

It will be recognized that while the imaging apparatus 120 as shown inFIG. 1 may be configured to capture x-ray images, any other alternativeimaging modality may also be used by the exemplary systems, methods, andinterfaces described herein. For example, the imaging apparatus 120 maybe configured to capture images, or image data, using isocentricfluoroscopy, bi-plane fluoroscopy, ultrasound, computed tomography (CT),multi-slice computed tomography (MSCT), magnetic resonance imaging(MRI), high frequency ultrasound (HIFU), optical coherence tomography(OCT), intra-vascular ultrasound (IVUS), two dimensional (2D)ultrasound, three dimensional (3D) ultrasound, four dimensional (4D)ultrasound, intraoperative CT, intraoperative MRI, etc. Further, it isto be understood that the imaging apparatus 120 may be configured tocapture a plurality of consecutive images (e.g., continuously) toprovide video frame data. In other words, a plurality of images takenover time using the imaging apparatus 120 may provide motion picturedata. Additionally, the images may also be obtained and displayed intwo, three, or four dimensions. In more advanced fauns, four-dimensionalsurface rendering of the heart or other regions of the body may also beachieved by incorporating heart data or other soft tissue data from anatlas map or from pre-operative image data captured by MRI, CT, orechocardiography modalities. Image datasets from hybrid modalities, suchas positron emission tomography (PET) combined with CT, or single photonemission computer tomography (SPECT) combined with CT, could alsoprovide functional image data superimposed onto anatomical data to beused to confidently reach target locations within the heart or otherareas of interest.

The display apparatus 130 and the computing apparatus 140 may beconfigured to display and analyze data such as, e.g., surrogateelectrical activation data, image data, mechanical motion data, etc.gathered, or collected, using the electrode apparatus 110 and theimaging apparatus 120 to noninvasively assist a user in locationselection of an implantable electrode. In at least one embodiment, thecomputing apparatus 140 may be a server, a personal computer, or atablet computer. The computing apparatus 140 may be configured toreceive input from input apparatus 142 and transmit output to thedisplay apparatus 130. Further, the computing apparatus 140 may includedata storage that may allow for access to processing programs orroutines and/or one or more other types of data, e.g., for driving agraphical user interface configured to noninvasively assist a user inlocation selection of an implantable electrode, etc.

The computing apparatus 140 may be operatively coupled to the inputapparatus 142 and the display apparatus 130 to, e.g., transmit data toand from each of the input apparatus 142 and the display apparatus 130.For example, the computing apparatus 140 may be electrically coupled toeach of the input apparatus 142 and the display apparatus 130 using,e.g., analog electrical connections, digital electrical connections,wireless connections, bus-based connections, network-based connections,internet-based connections, etc. As described further herein, a user mayprovide input to the input apparatus 142 to manipulate, or modify, oneor more graphical depictions displayed on the display apparatus 130 toview and/or select one or more target or candidate locations of aportion of a patient's heart as further described herein.

Although as depicted the input apparatus 142 is a keyboard, it is to beunderstood that the input apparatus 142 may include any apparatuscapable of providing input to the computing apparatus 140 to perform thefunctionality, methods, and/or logic described herein. For example, theinput apparatus 142 may include a mouse, a trackball, a touchscreen(e.g., capacitive touchscreen, a resistive touchscreen, a multi-touchtouchscreen, etc.), etc. Likewise, the display apparatus 130 may includeany apparatus capable of displaying information to a user, such as agraphical user interface 132 including graphical depictions of anatomyof a patient's heart, images of a patient's heart, graphical depictionsof locations of one or more electrodes, graphical depictions of one ormore target or candidate locations, alphanumeric representations of oneor more values, graphical depictions or actual images of implantedelectrodes and/or leads, etc. For example, the display apparatus 130 mayinclude a liquid crystal display, an organic light-emitting diodescreen, a touchscreen, a cathode ray tube display, etc.

The graphical user interfaces 132 displayed by the display apparatus 130may include, or display, one or more regions used to display graphicaldepictions, to display images, to allow selection of one or more regionsor areas of such graphical depictions and images, etc. As used herein, a“region” of a graphical user interface 132 may be defined as a portionof the graphical user interface 132 within which information may bedisplayed or functionality may be performed. Regions may exist withinother regions, which may be displayed separately or simultaneously. Forexample, smaller regions may be located within larger regions, regionsmay be located side-by-side, etc. Additionally, as used herein, an“area” of a graphical user interface 132 may be defined as a portion ofthe graphical user interface 132 located with a region that is smallerthan the region it is located within.

The processing programs or routines stored and/or executed by thecomputing apparatus 140 may include programs or routines forcomputational mathematics, matrix mathematics, decomposition algorithms,compression algorithms (e.g., data compression algorithms), calibrationalgorithms, image construction algorithms, signal processing algorithms(e.g., Fourier transforms, fast Fourier transforms, etc.),standardization algorithms, comparison algorithms, vector mathematics,or any other processing required to implement one or more exemplarymethods and/or processes described herein. Data stored and/or used bythe computing apparatus 140 may include, for example, image data fromthe imaging apparatus 120, electrical signal data from the electrodeapparatus 110, graphics (e.g., graphical elements, icons, buttons,windows, dialogs, pull-down menus, graphic areas, graphic regions, 3Dgraphics, etc.), graphical user interfaces, results from one or moreprocessing programs or routines employed according to the disclosureherein, or any other data that may be necessary for carrying out the oneand/or more processes or methods described herein.

In one or more embodiments, the exemplary systems, methods, andinterfaces may be implemented using one or more computer programsexecuted on programmable computers, such as computers that include, forexample, processing capabilities, data storage (e.g., volatile ornon-volatile memory and/or storage elements), input devices, and outputdevices. Program code and/or logic described herein may be applied toinput data to perform functionality described herein and generatedesired output information. The output information may be applied asinput to one or more other devices and/or methods as described herein oras would be applied in a known fashion.

The one or more programs used to implement the systems, methods, and/orinterfaces described herein may be provided using any programmablelanguage, e.g., a high level procedural and/or object orientatedprogramming language that is suitable for communicating with a computersystem. Any such programs may, for example, be stored on any suitabledevice, e.g., a storage media, that is readable by a general or specialpurpose program running on a computer system (e.g., including processingapparatus) for configuring and operating the computer system when thesuitable device is read for performing the procedures described herein.In other words, at least in one embodiment, the exemplary systems,methods, and/or interfaces may be implemented using a computer readablestorage medium, configured with a computer program, where the storagemedium so configured causes the computer to operate in a specific andpredefined manner to perform functions described herein. Further, in atleast one embodiment, the exemplary systems, methods, and/or interfacesmay be described as being implemented by logic (e.g., object code)encoded in one or more non-transitory media that includes code forexecution and, when executed by a processor, is operable to performoperations such as the methods, processes, and/or functionalitydescribed herein.

The computing apparatus 140 may be, for example, any fixed or mobilecomputer system (e.g., a controller, a microcontroller, a personalcomputer, minicomputer, tablet computer, etc.). The exact configurationof the computing apparatus 130 is not limiting, and essentially anydevice capable of providing suitable computing capabilities and controlcapabilities (e.g., graphics processing, etc.) may be used. As describedherein, a digital file may be any medium (e.g., volatile or non-volatilememory, a CD-ROM, a punch card, magnetic recordable tape, etc.)containing digital bits (e.g., encoded in binary, trinary, etc.) thatmay be readable and/or writeable by computing apparatus 140 describedherein. Also, as described herein, a file in user-readable format may beany representation of data (e.g., ASCII text, binary numbers,hexadecimal numbers, decimal numbers, graphically, etc.) presentable onany medium (e.g., paper, a display, etc.) readable and/or understandableby a user.

In view of the above, it will be readily apparent that the functionalityas described in one or more embodiments according to the presentdisclosure may be implemented in any manner as would be known to oneskilled in the art. As such, the computer language, the computer system,or any other software/hardware which is to be used to implement theprocesses described herein shall not be limiting on the scope of thesystems, processes or programs (e.g., the functionality provided by suchsystems, processes or programs) described herein.

As used herein, mechanical motion data may be defined as data relatingto the mechanical motion of one or more regions of a patient's heartsuch as portions of the walls of the patient's heart. It may bedesirable for target locations in a patient's heart for implantableelectrode placement to also have late mechanical motion timing (e.g.,later motion than other portions of the patient's heart, motion that islater than a selected threshold value or time, etc.). Mechanical motiondata may be measured and determined using the exemplary imagingapparatus 120 and the computing apparatus 140. For example, a pluralityof frames of image data may be captured using the imaging apparatus 120and analyzed by the computing apparatus to determine mechanical motioninformation, or data, of one or more regions of a patient's heart.

Local 3D motion of the heart wall can be decomposed into two components:the first component expresses change of distances between neighboringpoints and is referenced as a strain (e.g., contraction, when distancesdecrease or expansion, when distances increase, etc.) and the secondnon-strain component may not involve change of distances betweenneighboring points and may involve translation and/or rotation. Thestrain may be anisotropic. Specifically, a circumferential strain whencross sections (segments) perpendicular to the long axis of a heartchamber change length may be differentiated from a longitudinal strainwhen lines substantially parallel to long axis change length. Theexemplary imaging apparatus 120 described herein may be configured toprovide image data to provide graphical depictions of contraction andexpansion as a change in scale of a blood vessel tree, or in otherwords, as a change of distance between points, while rotation andtranslation are visualized without change of distances.

The imaging apparatus 120, which may be a computerized X-ray machine,may be directed at the patient's heart and activated to produce a timesequence of X-ray images of the heart area at the field of view. Inorder to expose blood vessels (e.g., such as the coronary vessels) atthe heart area under view, the X-ray images may be preferably obtainedunder angiography procedure by injecting contrast agent to the patient.Where the vessels to be detected are the coronary veins, the angiographymay be carried out after a balloon is inserted and inflated inside thevein, e.g., the coronary sinus, so as to prevent blood flow fromdispersing the contrast agent before the images are taken.

For example, a time sequence of two-dimensional X-ray projection imagesmay be captured by imaging apparatus of FIG. 1 and stored by thecomputing apparatus 140. The two-dimensional images may be angiogramstaken after the patient has been injected with contrast agent. The timesequence may include “snapshots” (e.g., angiographic cine-runs) of thecoronary vessel under the same projection angle during at least part ofthe cardiac cycle of the patient. Further, the projection direction maybe selected to be substantially orthogonal to the surface of the heartat the region of interest or to the main velocity component thereof.

The blood vessels of interest may be tracked through the time sequenceof images in order to identify the movements of the vessels through atleast part of the cardiac cycle. Tracking of blood vessels through thetime sequence of images may be performed by calculation of local areatransformations from one frame to the next, or by tracking selectedcontrol points in the detected vessels. Yet, in accordance with someembodiments, tracking the vessels may be performed by a hybridcombination of the two methods.

Examples of systems and/or imaging apparatus configured to capture anddetermine mechanical motion information may be described in U.S. Pat.App. Pub. No. 2005/0008210 to Evron et al. published on Jan. 13, 2005,U.S. Pat. App. Pub. No. 2006/0074285 to Zarkh et al. published on Apr.6, 2006, U.S. Pat. App. Pub. No. 2011/0112398 to Zarkh et al. publishedon May 12, 2011, U.S. Pat. App. Pub. No. 2013/0116739 to Brada et al.published on May 9, 2013, U.S. Pat. No. 6,980,675 to Evron et al. issuedon Dec. 27, 2005, U.S. Pat. No. 7,286,866 to Okerlund et al. issued onOct. 23, 2007, U.S. Pat. No. 7,308,297 to Reddy et al. issued on Dec.11, 2011, U.S. Pat. No. 7,308,299 to Burrell et al. issued on Dec. 11,2011, U.S. Pat. No. 7,321,677 to Evron et al. issued on Jan. 22, 2008,U.S. Pat. No. 7,346,381 to Okerlund et al. issued on Mar. 18, 2008, U.S.Pat. No. 7,454,248 to Burrell et al. issued on Nov. 18, 2008, U.S. Pat.No. 7,499,743 to Vass et al. issued on Mar. 3, 2009, U.S. Pat. No.7,565,190 to Okerlund et al. issued on Jul. 21, 2009, U.S. Pat. No.7,587,074 to Zarkh et al. issued on Sep. 8, 2009, U.S. Pat. No.7,599,730 to Hunter et al. issued on Oct. 6, 2009, U.S. Pat. No.7,613,500 to Vass et al. issued on Nov. 3, 2009, U.S. Pat. No. 7,742,629to Zarkh et al. issued on Jun. 22, 2010, U.S. Pat. No. 7,747,047 toOkerlund et al. issued on Jun. 29, 2010, U.S. Pat. No. 7,778,685 toEvron et al. issued on Aug. 17, 2010, U.S. Pat. No. 7,778,686 to Vass etal. issued on Aug. 17, 2010, U.S. Pat. No. 7,813,785 to Okerlund et al.issued on Oct. 12, 2010, U.S. Pat. No. 7,996,063 to Vass et al. issuedon Aug. 9, 2011, U.S. Pat. No. 8,060,185 to Hunter et al. issued on Nov.15, 2011, and U.S. Pat. No. 8,401,616 to Verard et al. issued on Mar.19, 2013, each of which are incorporated herein by reference in theirentireties.

Mechanical motion data, or information, may be provided to a user toassist the user in selecting a location for an implantable electrode. Anexemplary graphical user interface 132 depicting mechanical motioninformation of a portion of a patient's heart is shown in FIG. 2. Thegraphical user interface 132 is configured to depict at least a portionof blood vessel anatomy 200 of a patient's heart and mechanical motioninformation with respect to the blood vessel anatomy 200. As shown, theblood vessel anatomy 200 is the coronary sinus located proximate theleft ventricle of a patient. The blood vessel anatomy 200 furtherincludes a plurality of branches 202 of, e.g., the coronary sinus. Eachbranch, as well as multiple locations within each branch, may providecandidate site regions or locations for implantable electrodes.Implantable electrodes may be implanted in locations having the latestmechanical motion time. As used herein, mechanical motion time may bethe time between the onset of contraction and a common fiducial pointsuch as e.g., onset of QRS depolarization complex for that particularcardiac cycle on an external ECG lead.

As shown, the mechanical motion time may be represented by color/greyscaling, or coding, the blood vessel anatomy 200 according to a scale210. As shown, the scale 210 extends from dark grey/colors, whichcorrespond to about 40 milliseconds (ms), to light white/colors, whichcorrespond to about 240 ms. As such, a user may view the graphical userinterface 132 to see, or ascertain, the mechanical motions times of thedifferent regions of the heart (e.g., different regions of the bloodvessel anatomy). Additionally, the graphical user interface 132 mayalphanumerically depict the mechanical motion times 206 for one or moreregions 204 identified on blood vessel anatomy 200. Using the graphicaluser interface 132, a user may select a target, or candidate, location208 for implantation that may have the latest, or near the latest,mechanical motion time. As shown, the target location 208 may have amechanical motion time of 240 ms.

It may be desirable for target or candidate site regions or locationsfor implantable electrode placement to also have late electricalactivation times, in addition to late mechanical motion times. Theselected region, or location, such as region 208, however, may not havea late electrical activation time (e.g., indicating that the site maynot be as desirable even though the mechanical motion time indicated itsdesirability as an implant site). As such, it is beneficial to haveinformation about electrical activation times and mechanical motiontimes associated with a target or candidate site region to determine itssuitability for implant.

Electrical activation data of one or more regions of a patient's heartmay be determined using electrode apparatus 110 as shown in FIG. 1 andin FIGS. 3A-3B. The exemplary electrode apparatus 110 may be configuredto measure body-surface potentials of a patient 14 and, moreparticularly, torso-surface potentials of a patient 14. As shown in FIG.3A, the exemplary electrode apparatus 110 may include a set, or array,of electrodes 112, a strap 113, and interface/amplifier circuitry 116.The electrodes 112 may be attached, or coupled, to the strap 113 and thestrap 113 may be configured to be wrapped around the torso of patient 14such that the electrodes 112 surround the patient's heart. As furtherillustrated, the electrodes 112 may be positioned around thecircumference of a patient 14, including the posterior, lateral,posterolateral, and anterior locations of the torso of patient 14.

Further, the electrodes 112 may be electrically connected tointerface/amplifier circuitry 116 via wired connection 118. Theinterface/amplifier circuitry 116 may be configured to amplify thesignals from the electrodes 112 and provide the signals to the computingapparatus 140. Other exemplary systems may use a wireless connection totransmit the signals sensed by electrodes 112 to the interface/amplifiercircuitry 116 and, in turn, the computing apparatus 140, e.g., aschannels of data.

Although in the example of FIG. 3A the electrode apparatus 110 includesa strap 113, in other examples any of a variety of mechanisms, e.g.,tape or adhesives, may be employed to aid in the spacing and placementof electrodes 112. In some examples, the strap 113 may include anelastic band, strip of tape, or cloth. In other examples, the electrodes112 may be placed individually on the torso of a patient 14. Further, inother examples, electrodes 112 (e.g., arranged in an array) may be partof, or located within, patches, vests, and/or other means of securingthe electrodes 112 to the torso of the patient 14.

The electrodes 112 may be configured to surround the heart of thepatient 14 and record, or monitor, the electrical signals associatedwith the depolarization and repolarization of the heart after thesignals have propagated through the torso of patient 14. Each of theelectrodes 112 may be used in a unipolar configuration to sense thetorso-surface potentials that reflect the cardiac signals. Theinterface/amplifier circuitry 116 may also be coupled to a return orindifferent electrode (not shown) that may be used in combination witheach electrode 112 for unipolar sensing. In some examples, there may beabout 12 to about 50 electrodes 112 spatially distributed around thetorso of patient. Other configurations may have more or fewer electrodes112.

The computing apparatus 140 may record and analyze the torso-surfacepotential signals sensed by electrodes 112 and amplified/conditioned bythe interface/amplifier circuitry 116. The computing apparatus 140 maybe configured to analyze the signals from the electrodes 112 to providesurrogate electrical activation data such as surrogate electricalactivation times, e.g., representative of actual, or local, electricalactivation times of one or more regions of the patient's heart as willbe further described herein. Measurement of activation times can beperformed by picking an appropriate fiducial point (e.g., peak values,minimum values, minimum slopes, maximum slopes, zero crossings,threshold crossings, etc. of a near or far-field EGM) and measuring timebetween the onset of cardiac depolarization (e.g., onset of QRScomplexes) and the appropriate fiducial point (e.g., within theelectrical activity). The activation time between the onset of the QRScomplex (or the peak Q wave) to the fiducial point may be referred to asq-LV time.

Additionally, the computing apparatus 140 may be configured to providegraphical user interfaces depicting the surrogate electrical activationtimes obtained using the electrode apparatus 110. Exemplary systems,methods, and/or interfaces may noninvasively use the electricalinformation collected using the electrode apparatus 110 to identify,select, and/or determine whether one or more regions of a patient'sheart may be optimal, or desirable, for implantable electrode placement.

FIG. 3B illustrates another exemplary electrode apparatus 110 thatincludes a plurality of electrodes 112 configured to surround the heartof the patient 14 and record, or monitor, the electrical signalsassociated with the depolarization and repolarization of the heart afterthe signals have propagated through the torso of patient 14. Theelectrode apparatus 110 may include a vest 114 upon which the pluralityof electrodes 112 may be attached, or to which the electrodes 112 may becoupled. In at least one embodiment, the plurality, or array, ofelectrodes 112 may be used to collect electrical information such as,e.g., surrogate electrical activation times. Similar to the electrodeapparatus 110 of FIG. 3A, the electrode apparatus 110 of FIG. 3B mayinclude interface/amplifier circuitry 116 electrically coupled to eachof the electrodes 112 through a wired connection 118 and configured totransmit signals from the electrodes 112 to computing apparatus 140. Asillustrated, the electrodes 112 may be distributed over the torso ofpatient 14, including, for example, the anterior, lateral, and posteriorsurfaces of the torso of patient 14.

The vest 114 may be formed of fabric with the electrodes 112 attached tothe fabric. The vest 114 may be configured to maintain the position andspacing of electrodes 112 on the torso of the patient 14. Further, thevest 114 may be marked to assist in determining the location of theelectrodes 112 on the surface of the torso of the patient 14. In someexamples, there may be about 25 to about 256 electrodes 112 distributedaround the torso of the patient 14, though other configurations may havemore or fewer electrodes 112.

As described herein, the electrode apparatus 110 may be configured tomeasure electrical information (e.g., electrical signals) representingdifferent regions of a patient's heart. More specifically, activationtimes of different regions of a patient's heart can be approximated fromsurface electrocardiogram (ECG) activation times measured using surfaceelectrodes in proximity to surface areas corresponding to the differentregions of the patient's heart.

A diagram of exemplary surface locations of patient 14 mapped to regionsof a patient's heart 12 to be measured using external electrodeapparatus are shown in FIG. 4. As shown, a left anterior surfacelocation 220 may correspond to a left anterior left ventricle region 230of the patient's heart 12, a left lateral surface location 222 maycorrespond to a left lateral left ventricle region 232 of the patient'sheart 12, a left posterolateral surface location 224 may correspond to aposterolateral left ventricle region 234 of the patient's heart 12, anda posterior surface location 226 may correspond to a posterior leftventricle region 236 of the patient's heart 12. Thus, the electricalsignals measured at the left anterior surface location 220 may berepresentative, or surrogates, of electrical signals of the leftanterior left ventricle region 230, electrical signals measured at theleft lateral surface location 222 may be representative, or surrogates,of electrical signals of the left lateral left ventricle region 232,electrical signals measured at the left posterolateral surface location224 may be representative, or surrogates, of electrical signals of theposterolateral left ventricle region 234, and electrical signalsmeasured at the posterior surface location 226 may be representative, orsurrogates, of electrical signals of the posterior left ventricle region236.

Unipolar ECG data collected from electrode apparatus 110 such as, e.g.,depicted in FIGS. 3A-3B, may be used to derive a sequence of ventricularactivation. Information on regional, or local, ventricular activationmay be inferred by looking at activation times corresponding to certainanatomic regions.

A diagram depicting late surrogate activation time of a posterolateralsurface location of a patient measured using external electrodes isdepicted in FIG. 5. As shown, ECG activation data shows late activation(e.g., about 150 ms) in the posterolateral surface location 224, andthus the posterolateral left ventricle region 234, which corresponds tothe posterolateral surface location area 224, may be a target, orcandidate, implantation site region for an implanted electrode. Further,samples 230 from the posterolateral surface location 224 show broad,tall, and dominant R-waves 232 that may further indicate that theposterolateral left ventricle region 234 may be an optimal candidate, ortarget, implantation site region for an implanted electrode.

So that the computing apparatus 140 is aware of where the electricalsignals measured using the external electrodes 112 of the electrodeapparatus 110 are coming from (e.g., such as the various surfaceslocations, or areas, for example, the left anterior surface location220, the left lateral surface location 222, the left posterolateralsurface location 224, the posterior surface location 226 etc.), theexternal electrodes 112 may be associated with one or more of thesurface locations, or areas, and thus with one or more locations, orregions, of the patient's heart 14. Any suitable technique forassociating the external electrodes (e.g., signals therefrom) with oneor more locations, or regions, of the patient's heart 14 may be used.For example, in one or more embodiments, to associate the externalelectrodes 112 with one or more surface locations and/or regions of thepatient's heart, a user may particularly place, or locate, certainelectrodes on particular locations of the patient's torso (e.g., one ormore electrodes being in proximity to the region of the blood vesselanatomy for which measurements are to be provided). For example, one ormore electrodes may be configured to measure, or be associated with, theleft lateral surface location 222, and thus, a user may place such oneor more electrodes on the left lateral surface location 232 (e.g., theone or more electrodes may be located proximate the left lateral surfacelocation 232). In at least one embodiment, a band or vest may alreadyhave the electrodes 112 located in proper positions to correspond tovarious surface locations of a patient, and thus, a user may simplyposition the band or vest about the patient to properly locate theexternal electrodes 112 about the patient. The band or vest may furtherinclude indications of where each portion of the band or vest should belocated about the patient.

Further, the external electrodes 112 may be associated with, or linkedto, one or more surface locations and/or regions of the patient's heartusing the imaging apparatus 120 described herein. For example, theelectrodes 112 and/or markers (e.g., washers) may be visible in one ormore images captured by the image apparatus 120. The markers may belocated known distances and/or locations about the electrodes 112 suchthat markers may indicate where the electrodes 112 are located.

Using the imaging apparatus 120, which may image the electrodes 112and/or markers with respect to at least a portion of the patient's heart12, the electrodes 112 may be associated with the regions of thepatient's heart 12 that the electrodes 112 are located in closestproximity to (e.g., about 0.5 centimeters to about 10 cm). For example,a first group of external electrodes 112 (e.g., a first group includingone or more external electrodes) may be determined to be located inproximity to the left lateral left ventricular region 232 using imagescaptured by the imaging apparatus 120, and thus, the first group ofexternal electrodes 112 may be associated with the left lateral leftventricular region 232 of the patient's heart 12.

A diagram of surface locations of external markers associated with oneor more electrodes used to measure surrogate electrical activation timesis depicted in FIG. 6. As shown, a first marker 240, a second marker242, a third marker 244, and a fourth marker 246 are depicted on patient14. Each of the markers 240, 242, 244, 246 may be associated with one ormore external electrodes 112. The imaging apparatus 120 may capture oneor more images of a portion of the patient's heart and the markers 240,242, 244, 246, and the computing apparatus 140 may determine whichmarkers, and thus, which external electrodes, are proximate to the oneor more different regions of the patient's heart.

The locations of the markers may be further depicted on exemplarygraphical user interfaces depicting a portion of the patient's heart.For example, an exemplary graphical user interface 250 depicting bloodvessel anatomy 252 of a portion of a patient's heart, mechanical motioninformation associated with the blood vessel anatomy 252 (e.g., themechanical motion information being color coded/grey scaled on the bloodvessel anatomy), and the locations of the external markers 240, 242,244, 246 with respect to the blood vessel anatomy 252 is shown in FIG.7.

An exemplary method 260 of assisting in noninvasive location selectionfor an implantable electrode is depicted in FIG. 8. The exemplary method260 may be described as being non-invasive because no lead, electrode,probe, or other device may be implanted into the patient when using theexemplary method. Further, the exemplary method 260 may be executedusing the systems, apparatus, and graphical user interfaces describedherein.

The exemplary method 260 may include displaying blood vessel anatomy 262of at least a portion of a patient's heart, e.g., using a graphical userinterface on display apparatus. Although the exemplary method 260displays blood vessel anatomy of a patient's heart, it is to beunderstood that any part of a patient's anatomy may be displayed. Themethod 260 may further include measuring mechanical motion 264 of theblood vessel anatomy of the patient's heart and displaying mechanicalmotion information 266 of the blood vessel anatomy, e.g., using agraphical user interface on a display apparatus. An exemplary graphicaluser interface 280 including blood vessel anatomy 282 and gray-scaledmechanical motion information is shown in FIG. 9A. The blood vesselanatomy and mechanical motion information thereof may be captured usingthe imaging apparatus 120 described herein, which may be configured toimage at least a portion of blood vessel anatomy of the patient's heartand provide image data used by the computing apparatus 140 to providemechanical motion information or data.

A user may view and/or use the graphical user interface 280 of FIG. 9Ato determine, or identify, one or more candidate site regions of thedisplayed portion of the patient's heart for implantation of implantableelectrodes. For example, a user may view the mechanical motioninformation, e.g., grey-scaling or color-coding applied to the bloodvessel anatomy in FIG. 9A, and identify a candidate site region 284 ofthe patient's heart based on the mechanical motion information. Forexample, a user may identify one or more regions having, e.g.,mechanical motion times greater than a threshold, having the longestmechanical motion time, etc. A user may select the identified candidateregion 284 using the graphical user interface 280 and input apparatus142 of the computing apparatus 140. For example, if the input apparatus142 is a touchscreen, the user may touch the identified candidate siteregion 284 with their finger or stylus. Further, for example, if theinput apparatus 142 is a mouse, a user may “click on” the identifiedcandidate site region 284 using the mouse.

Although a user is described as identifying the candidate region 284,the computing apparatus 140 and/or another portion of the system 100 maybe configured to identify the candidate site region 284. For example,the computing apparatus 140 may be configured to automatically identifyone or more regions of the blood vessel anatomy based on the mechanicalmotion information, e.g., implantation site region(s) having the longestmechanical motion time, implantation site region(s) have a mechanicalmotion time greater than or equal to a threshold value, etc.

The exemplary method 260 may further include measuring surrogateelectrical activation time 270 of the identified candidate site region284 using one or more external electrodes 112 located proximate tissueof a patient (e.g., skin of the patient's torso). As described hereinthe surrogate electrical activation time of a region, such as thecandidate site region 284, may be measured using one or more externalelectrodes proximate the implantation site region.

In at least one embodiment, the positions of the external electrodes maybe identified with respect to the implantation site region of the bloodvessel anatomy using imaging apparatus 120, and the one or more externalelectrodes that are closest to a particular implantation site region(e.g., determined to be closest) may be used to measure surrogateelectrical activation time for the implantation site region. In at leastone embodiment, each external electrode may already be associated with aparticular implantation site region of the blood vessel anatomy, andthus, the external electrodes already associated with an implantationsite region may be used to measured surrogate electrical activation timefor the implantation site region.

After the implantation site region of the blood vessel anatomy has beenselected 268 and the surrogate electrical activation time has beenmeasured 270, the exemplary method 260 may include displaying themeasured surrogate activation time for the identified implantation siteregion 284. For example, the measured activation time 286 may bealphanumerically depicted proximate the identified implantation siteregion 284 of the blood vessel anatomy 282 on the graphical userinterface 280 as shown in FIG. 9B. If the identified implantation siteregion does not have a desirable surrogate electrical activation time286 (e.g., the implantation site region does not have a late electricalactivation time, the electrical activation time is not greater than orequal to a threshold value, etc.), a user may select anotherimplantation site region of the blood vessel anatomy 282, e.g., as shownby the arrow 271 looping back to identifying an implantation site regionof blood vessel anatomy 268.

A user may then use the exemplary systems and interfaces describedherein to navigate an implantable electrode to one or more of theidentified implantation site regions 274. For example, the systems andgraphical user interfaces described herein may provide real-timenavigation of an implantable electrode (e.g., located on a lead, awireless electrode, located on a device, etc.) to an implantation siteregion such as the identified implantation site region (e.g., a siteregion identified noninvasively as being associated with a latemechanical motion time and a late electrical activation time).

Although the exemplary method 270 may measure the surrogate electricalactivation time 270 after an implantation site region of the bloodvessel anatomy has been identified 268, it is to be understood that theexemplary systems, methods, and/or interfaces may be configured tomeasure surrogate electrical activation time 270 of a plurality ofimplantation site regions of the patient's heart prior to theidentification of a particular region 268 and/or may display themeasured surrogate electrical activation times 272 of all theimplantation site regions. For example, an exemplary graphical userinterface 290 depicting a portion of a patient's heart and blood vesselanatomy 292 thereof including mechanical motion information such asgrey-scaling and alphanumeric values representing mechanical motiontimings is shown in FIG. 10. The exemplary graphical user interface 290further depicts surrogate activation times 296 for each of the firstimplantation site region 293, second implantation site region 294, thirdimplantation site region 295, and fourth implantation site region 296.

One or more exemplary systems, methods, and/or interfaces may usemeasured mechanical motion data and measured surrogate electricalactivation times to identify one or more candidate and/or target siteregions for implantation, or location selection, of an implantableelectrode for delivering therapy (e.g., from a larger number ofpotential implantation sites). An exemplary method 300 of assisting insuch noninvasive location selection for an implantable electrode isdepicted in FIG. 11. Generally, the exemplary method 300 may (e.g.,automatically or by user selection) determine one or more candidateand/or target site regions for implanting an implantable electrode fordelivery of therapy based on mechanical motion information of a portionof a patient's heart, surrogate electrical activation times ofimplantation site regions of the patient's heart, and, optionally,information relating to scar risk for one or more implantation siteregions of the patient's heart.

The exemplary method 300 may include measuring mechanical motion 302 ofa plurality of implantation site regions (e.g., identified site regions,such as, for example, the first implantation site region 293, the secondimplantation site region 294, the third implantation site region 295,and the fourth implantation site region 296 shown on the graphical userinterface 290 of FIG. 10) of a portion of blood vessel anatomy of apatient's heart using, e.g., imaging apparatus 120, to providemechanical motion data, or information, such as mechanical contractiontimes. Each implantation site region may be a defined portion or area ofthe patient's heart and/or of the blood vessel anatomy of the patient'sheart. Further, each implantation site region may be different that theother implantation site regions. In other words, the implantation siteregions may not be duplicative.

Surrogate electrical activation time may be measured 304 for each of theimplantation site regions using, e.g., electrode apparatus 110, suchthat each implantation site region has a mechanical contraction time andsurrogate electrical activation time associated therewith (e.g.,measurements using one electrode of the electrode apparatus for eachsite region, averaged measurements from multiple electrodes of theelectrode apparatus for each site region, etc.).

In one exemplary embodiment, the measured mechanical contraction timesand measured surrogate electrical activation times for the firstimplantation site region 293, the second implantation site region 294,the third implantation site region 295, and the fourth implantation siteregion 296 of the portion of a patient's heart from the graphical userinterface 290 of FIG. 10 is depicted below in Table 1.

TABLE 1 Mechanical Electrical Site #1 Times Times 1 163 ms  50 ms 2 184ms 100 ms 3 222 ms 120 ms 4 240 ms  60 ms

The exemplary method 300 may then determine one or more candidate siteregions 306 from the plurality of implantation site regions based on themeasured mechanical contraction times and measured electrical activationtimes. The determination of one or more candidate site regions 306 mayuse comparisons, percentages, thresholds, averages, means, peak-to-peakamplitudes, maximum slope, minimum slope, other motion curve metrics,etc. of the measured mechanical contraction times and/or the measuredsurrogate electrical activation times.

For example, each of the mechanical contraction times may be compared toa threshold value or time to determine whether the implantation siteregion may be a candidate site region. The threshold value or time maybe a fixed, or set, value determined, e.g., by a user or the computingapparatus, or may be based or calculated on other data such as some orall of the measured mechanical contraction times for the implantationsite regions. For example, a mechanical motion threshold value or timemay be based on the latest mechanical motion contraction time measuredamong the implantation site regions.

In the example depicted in FIG. 10 and Table 1, the fourth implantationsite region 296 has the latest mechanical contraction time, which is 240ms. The mechanical motion threshold value may be a selected percentage,such as, e.g., 50%, 60%, 65%, 70%, 75%, 80%, 90%, 95%, etc., of thelatest mechanical contraction time. In this example, the selectedpercentage may be 75%, which would yield a mechanical motion thresholdof 180 ms (e.g., 240 ms×75%=180 ms).

Each of the surrogate electrical activation times may be compared to athreshold value or time to determine whether the implantation siteregion may be a candidate site region. The threshold value or time maybe a fixed, or set, value determined, e.g., by a user or the computingapparatus, or may be based or calculated on other data such as some orall of the measured surrogate electrical activation times for theimplantation site regions. For example, an electrical activationthreshold value or time may be based on the latest surrogate electricalactivation time measured among the implantation site regions.

In the example depicted in FIG. 10 and Table 1, the third implantationsite region 295 has the latest surrogate electrical activation time,which is 120 ms. The electrical activation threshold value may be aselected percentage, such as, e.g., 50%, 60%, 65%, 70%, 75%, 80%, 90%,95%, etc., of the latest surrogate electrical activation time. In thisexample, the selected percentage may be 75%, which would yield anelectrical activation threshold of 90 ms (e.g., 120 ms×75%=90 ms).

Using the mechanical motion threshold value and the electricalactivation threshold value, the exemplary method 300 may determine oneor more candidate site regions 306. For example, an implantation siteregion may be identified or selected as a candidate site region if theimplantation site region has a mechanical contraction time greater thanor equal to the mechanical motion threshold and a surrogate electricalactivation time greater than or equal to the electrical activationthreshold. As such, in the example of FIG. 10 and Table 1, the candidatesites must have a mechanical contraction time greater than or equal to180 ms, i.e., the mechanical motion threshold value, and a surrogateelectrical activation time greater than or equal to 90 ms, i.e., theelectrical activation threshold value. Using such thresholds, theexemplary method 300 may determine that the second site 294 and thirdsite 295 may be candidate site regions 306 for implantation of animplantable electrode to deliver therapy.

Additionally, if none of the implantation site region satisfies both theelectrical activation threshold value and the mechanical motionthreshold value, the threshold values may be decreased by a selectedvalue or percentage, and each of the implantation site regions may bere-evaluated. In at least one embodiment, the selected percentages usedto calculate the threshold values may be decreased by a fixed amountsuch as, e.g., 5%. Likewise, if all the implantation site regionssatisfy both the electrical activation threshold value and themechanical motion threshold value, the threshold values may be increasedby a selected value or percentage, and each of the implantation siteregions may be re-evaluated. Further, if only one implantation siteregion satisfies the electrical activation threshold value and themechanical motion threshold value, this site region may be selected forimplantation of the electrode.

The exemplary method 300 may also include graphically identifying theone or more candidate site regions 310 for implantation of theimplantable electrode, e.g., using the exemplary graphical userinterfaces described herein, etc. For example, the candidate siteregions may be highlighted on a graphical user interface, or arrows maybe depicted pointing to the candidate site regions selected from theoriginally or initially identified potential site regions.

Each of the one or more candidate site regions may have an associatedscar risk. As such, the exemplary systems, methods, and graphical userinterfaces may optionally consider the scar risk for each of the one ormore candidate site regions to further selected one or more target siteregions from the candidate site regions (e.g., reducing the number ofsite regions that may be desirable for electrode implantation). Forexample, the exemplary method 300 may include determining a scar riskfor each of the candidate site regions 308, and based on the scar risk,identify the target site regions from the candidate site regions 310.Similar to the exemplary method 260, the exemplary method 300 mayinclude navigating an implantable electrode to one or more of thecandidate and/or target site regions 312 (e.g., after the candidate ortarget site region has been selected noninvasively). For example, thesystems and graphical user interfaces described herein may providereal-time navigation of an implantable electrode (e.g., located on alead, a wireless electrode, located on a device, etc.) to animplantation site region (e.g., a site region identified noninvasivelyusing both mechanical motion times and electrical activation times, aswell as optionally scar risk information).

As described herein, scar risk information may be used to further reducethe number candidate sites suitable for electrode implant. Although, anyprocess of reducing the number of candidate sites based on scarinformation may be used, one exemplary method 350 of using scar riskinformation for noninvasively selecting implantation site regions isdepicted in FIGS. 12-14. The exemplary method 350 may first set the scarrisk score for a particular region (e.g., selected from the one or morecandidate regions, etc.) to zero. The mechanical motion data and/orsurrogate electrical data for that particular region may be evaluated todetermine the scar risk score. For example, the mechanical motion data,or curve, may be evaluated as described with reference to FIG. 13, andthe surrogate electrical activation data, or curve, may be evaluated asdescribed with reference to FIG. 14.

The mechanical motion data, or curves, for the first implantation siteregion 293, the second implantation site region 294, the thirdimplantation site region 295, and the fourth implantation site region296 during one cardiac cycle are depicted in FIG. 13. As shown, themaximum peak-to-peak values for the first implantation site region 293,the second implantation site region 294, the third implantation siteregion 295, and the fourth implantation site region 296 are 11millimeters (mm), 12 mm, 8 mm, and 7 mm, respectively.

A threshold value may be determined based on the maximum peak-to-peakamplitude. In this example, the maximum peak-to-peak amplitude of theimplantation site regions may be 12 mm. For example, a threshold forindication of scarring may be 10% of the maximum peak-to-peak amplitude,and therefore, the threshold may be 1.2 mm.

The exemplary method 300 may increase the scar risk score for aparticular implantation site region by one 358 if the implantation siteregion's peak-to-peak amplitude is less than the threshold value 354(which, e.g., is 10% of the maximum peak-to-peak amplitude of all theimplantation site regions). In the example depicted in FIG. 13, none ofthe first implantation site region 293, the second implantation siteregion 294, the third implantation site region 295, and the fourthimplantation site region 296 have a peak-to-peak amplitude less than 1.2mm, and thus, the scar risk score for each of the first implantationsite region 293, the second implantation site region 294, the thirdimplantation site region 295, and the fourth implantation site region296 is not increased.

The surrogate electrical activation data, or curves, for the firstimplantation site region 293, the second implantation site region 294,the third implantation site region 295, and the fourth implantation siteregion 296 for the same cardiac cycle as in FIG. 13 are depicted in FIG.14. As shown, the maximum peak-to-peak values for the first implantationsite region 293, the second implantation site region 294, the thirdimplantation site region 295, and the fourth implantation site region296 are 7 millivolts (mV), 0.5 mV, 5.3 mV, and 5.4 mV, respectively. Athreshold value may be selected to be a minimum value such as, e.g., 1mV.

The exemplary method 300 may increase the scar risk score for aparticular implantation site region by one 358 if the implantation siteregion's peak-to-peak amplitude is less than the threshold value 356(e.g., 1 mV). In the example depicted in FIG. 14, only the secondimplantation site region 294 has a peak-to-peak amplitude less than 1mV, and thus, the scar risk score for only the second implantation siteregion 294 is increased by one 358.

Additionally, the surrogate electrical activation data for eachimplantation site region may be evaluated using other metrics that mayindicate scar risk such as, e.g., fractionations, ST segment elevation,etc. If the other metrics indicate scar risk (e.g., such as inclusion offractions and/or ST segment elevations), the process 356 may increasethe scar risk score for the particular site by one 358. As shown in FIG.14, the second implantation site region 294 indicates bothfractionations and ST segment elevation, and thus, the scar risk scorefor the second implantation site region 294 is increased by one 358.

The exemplary method 350 may then update the scar risk score 360 foreach of the candidate site regions. The scar risk score, or othermetrics related to scarring, may be evaluated by any other methodsand/or processes described herein such as, e.g., exemplary method 300 inprocess 308. As described herein, the second and third implantation siteregions 294, 295 were selected as candidate sites in process 306 ofexemplary method 300. Since the scar risk for the second implantationsite region 294 is higher (e.g., the scar risk score for the secondimplantation site region 294 is one, which may be indicative of scar)than the scar risk score for the third implantation site region 295(e.g., the scar risk score for the third implantation site region 295 iszero), the third implantation site region 295 may be identified, orselected, 310 as a target site region in the exemplary method 300. Asdescribed herein, after a target site region has been identified 310, auser may then navigate an implantable electrode to the target siteregion 312 (e.g., in this example, the user may navigate an implantableelectrode to the third implantation site region 295).

The implantable electrodes that may be implanted using the exemplarysystems, methods, and graphical user interfaces described herein may bepart of an implantable medical device (IMD) and/or located on one ormore leads configured to be located proximate one or more portions of apatient's heart. For example, the exemplary systems, methods andprocesses may be used by an exemplary therapy system 10 described hereinwith reference to FIGS. 15-17.

FIG. 15 is a conceptual diagram illustrating an exemplary therapy system10 that may be used to deliver pacing therapy to a patient 14. Patient14 may, but not necessarily, be a human. The therapy system 10 mayinclude an implantable medical device 16 (IMD), which may be coupled toleads 18, 20, 22. The IMD 16 may be, e.g., an implantable pacemaker,cardioverter, and/or defibrillator, that provides electrical signals tothe heart 12 of the patient 14 via electrodes coupled to one or more ofthe leads 18, 20, 22 (e.g., electrodes that may be implanted inaccordance with the description herein, such as, with use ofnon-invasive selection of implantation site regions).

The leads 18, 20, 22 extend into the heart 12 of the patient 14 to senseelectrical activity of the heart 12 and/or to deliver electricalstimulation to the heart 12. In the example shown in FIG. 15, the rightventricular (RV) lead 18 extends through one or more veins (not shown),the superior vena cava (not shown), and the right atrium 26, and intothe right ventricle 28. The left ventricular (LV) coronary sinus lead 20extends through one or more veins, the vena cava, the right atrium 26,and into the coronary sinus 30 to a region adjacent to the free wall ofthe left ventricle 32 of the heart 12. The right atrial (RA) lead 22extends through one or more veins and the vena cava, and into the rightatrium 26 of the heart 12.

The IMD 16 may sense, among other things, electrical signals attendantto the depolarization and repolarization of the heart 12 via electrodescoupled to at least one of the leads 18, 20, 22. The IMD 16 may beconfigured to determine or identify effective electrodes located on theleads 18, 20, 22 using the exemplary methods and processes describedherein. In some examples, the IMD 16 provides pacing therapy (e.g.,pacing pulses) to the heart 12 based on the electrical signals sensedwithin the heart 12. The IMD 16 may be operable to adjust one or moreparameters associated with the pacing therapy such as, e.g., AV delayand other various timings, pulse wide, amplitude, voltage, burst length,etc. Further, the IMD 16 may be operable to use various electrodeconfigurations to deliver pacing therapy, which may be unipolar,bipolar, quadripoloar, or further multipolar. For example, a multipolarlead may include several electrodes that can be used for deliveringpacing therapy. Hence, a multipolar lead system may provide, or offer,multiple electrical vectors to pace from. A pacing vector may include atleast one cathode, which may be at least one electrode located on atleast one lead, and at least one anode, which may be at least oneelectrode located on at least one lead (e.g., the same lead, or adifferent lead) and/or on the casing, or can, of the IMD. Whileimprovement in cardiac function as a result of the pacing therapy mayprimarily depend on the cathode, the electrical parameters likeimpedance, pacing threshold voltage, current drain, longevity, etc. maybe more dependent on the pacing vector, which includes both the cathodeand the anode. The IMD 16 may also provide defibrillation therapy and/orcardioversion therapy via electrodes located on at least one of theleads 18, 20, 22. Further, the IMD 16 may detect arrhythmia of the heart12, such as fibrillation of the ventricles 28, 32, and deliverdefibrillation therapy to the heart 12 in the form of electrical pulses.In some examples, IMD 16 may be programmed to deliver a progression oftherapies, e.g., pulses with increasing energy levels, until afibrillation of heart 12 is stopped.

FIG. 16A-16B are conceptual diagrams illustrating the IMD 16 and theleads 18, 20, 22 of therapy system 10 of FIG. 15 in more detail. Theleads 18, 20, 22 may be electrically coupled to a therapy deliverymodule (e.g., for delivery of pacing therapy), a sensing module (e.g.,for sensing one or more signals from one or more electrodes), and/or anyother modules of the IMD 16 via a connector block 34. In some examples,the proximal ends of the leads 18, 20, 22 may include electricalcontacts that electrically couple to respective electrical contactswithin the connector block 34 of the IMD 16. In addition, in someexamples, the leads 18, 20, 22 may be mechanically coupled to theconnector block 34 with the aid of set screws, connection pins, oranother suitable mechanical coupling mechanism.

Each of the leads 18, 20, 22 includes an elongated insulative lead body,which may carry a number of conductors (e.g., concentric coiledconductors, straight conductors, etc.) separated from one another byinsulation (e.g., tubular insulative sheaths). In the illustratedexample, bipolar electrodes 40, 42 are located proximate to a distal endof the lead 18. In addition, the bipolar electrodes 44, 45, 46, 47 arelocated proximate to a distal end of the lead 20 and the bipolarelectrodes 48, 50 are located proximate to a distal end of the lead 22.

The electrodes 40, 44, 44, 45, 46, 47, 48 may take the form of ringelectrodes, and the electrodes 42, 50 may take the form of extendablehelix tip electrodes mounted retractably within the insulative electrodeheads 52, 54, 56, respectively. Each of the electrodes 40, 42, 44, 45,46, 47, 48, 50 may be electrically coupled to a respective one of theconductors (e.g., coiled and/or straight) within the lead body of itsassociated lead 18, 20, 22, and thereby coupled to respective ones ofthe electrical contacts on the proximal end of the leads 18, 20, 22.

Additionally, electrodes 44, 45, 46 and 47 may have an electrode surfacearea of about 5.3 mm² to about 5.8 mm². Electrodes 44, 45, 46, and 47may also be referred to as LV1, LV2, LV3, and LV4, respectively. The LVelectrodes (i.e., left ventricle electrode 1 (LV 1) 44, left ventricleelectrode 2 (LV2) 45, left ventricle electrode 3 (LV3) 46, and leftventricle 4 (LV4) 47 etc.) on the lead 20 can be spaced apart atvariable distances. For example, electrode 44 may be a distance of,e.g., about 21 millimeters (mm), away from electrode 45, electrodes 45and 46 may be spaced a distance of, e.g. about 1.3 mm to about 1.5 mm,away from each other, and electrodes 46 and 47 may be spaced a distanceof, e.g. 20 mm to about 21 mm, away from each other.

The electrodes 40, 42, 44, 45, 46, 47, 48, 50 may further be used tosense electrical signals (e.g., morphological waveforms withinelectrograms (EGM)) attendant to the depolarization and repolarizationof the heart 12. The sensed electrical signals may be used to determinewhich of the electrodes 40, 42, 44, 45, 46, 47, 48, 50 are the mosteffective in improving cardiac function. The electrical signals areconducted to the IMD 16 via the respective leads 18, 20, 22. In someexamples, the IMD 16 may also deliver pacing pulses via the electrodes40, 42, 44, 45, 46, 47, 48, 50 to cause depolarization of cardiac tissueof the patient's heart 12. In some examples, as illustrated in FIG. 16A,the IMD 16 includes one or more housing electrodes, such as housingelectrode 58, which may be formed integrally with an outer surface of ahousing 60 (e.g., hermetically-sealed housing) of the IMD 16 orotherwise coupled to the housing 60. Any of the electrodes 40, 42, 44,45, 46, 47, 48 and 50 may be used for unipolar sensing or pacing incombination with housing electrode 58. In other words, any of electrodes40, 42, 44, 45, 46, 47, 48, 50, 58 may be used in combination to form asensing vector, e.g., a sensing vector that may be used to evaluateand/or analyze the effectiveness of pacing therapy. It is generallyunderstood by those skilled in the art that other electrodes can also beselected to define, or be used for, pacing and sensing vectors. Further,any of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, which are notbeing used to deliver pacing therapy, may be used to sense electricalactivity during pacing therapy.

As described in further detail with reference to FIG. 16A, the housing60 may enclose a therapy delivery module that may include a stimulationgenerator for generating cardiac pacing pulses and defibrillation orcardioversion shocks, as well as a sensing module for monitoring thepatient's heart rhythm. The leads 18, 20, 22 may also include elongatedelectrodes 62, 64, 66, respectively, which may take the form of a coil.The IMD 16 may deliver defibrillation shocks to the heart 12 via anycombination of the elongated electrodes 62, 64, 66 and the housingelectrode 58. The electrodes 58, 62, 64, 66 may also be used to delivercardioversion pulses to the heart 12. Further, the electrodes 62, 64, 66may be fabricated from any suitable electrically conductive material,such as, but not limited to, platinum, platinum alloy, and/or othermaterials known to be usable in implantable defibrillation electrodes.Since electrodes 62, 64, 66 are not generally configured to deliverpacing therapy, any of electrodes 62, 64, 66 may be used to senseelectrical activity (e.g., for use in determining electrodeeffectiveness, for use in analyzing pacing therapy effectiveness, etc.)and may be used in combination with any of electrodes 40, 42, 44, 45,46, 47, 48, 50, 58. In at least one embodiment, the RV elongatedelectrode 62 may be used to sense electrical activity of a patient'sheart during the delivery of pacing therapy (e.g., in combination withthe housing electrode 58 forming a RV elongated coil, or defibrillationelectrode-to-housing electrode vector).

The configuration of the exemplary therapy system 10 illustrated inFIGS. 15-17 is merely one example. In other examples, the therapy systemmay include epicardial leads and/or patch electrodes instead of or inaddition to the transvenous leads 18, 20, 22 illustrated in FIG. 15.Further, in one or more embodiments, the IMD 16 need not be implantedwithin the patient 14. For example, the IMD 16 may deliver variouscardiac therapies to the heart 12 via percutaneous leads that extendthrough the skin of the patient 14 to a variety of positions within oroutside of the heart 12. In one or more embodiments, the system 10 mayutilize wireless pacing (e.g., using energy transmission to theintracardiac pacing component(s) via ultrasound, inductive coupling, RF,etc.) and sensing cardiac activation using electrodes on the can/housingand/or on subcutaneous leads.

In other examples of therapy systems that provide electrical stimulationtherapy to the heart 12, such therapy systems may include any suitablenumber of leads coupled to the IMD 16, and each of the leads may extendto any location within or proximate to the heart 12. For example, otherexamples of therapy systems may include three transvenous leads locatedas illustrated in FIGS. 15-17. Still further, other therapy systems mayinclude a single lead that extends from the IMD 16 into the right atrium26 or the right ventricle 28, or two leads that extend into a respectiveone of the right atrium 26 and the right ventricle 28.

FIG. 17A is a functional block diagram of one exemplary configuration ofthe IMD 16. As shown, the IMD 16 may include a control module 81, atherapy delivery module 84 (e.g., which may include a stimulationgenerator), a sensing module 86, and a power source 90.

The control module 81 may include a processor 80, memory 82, and atelemetry module 88. The memory 82 may include computer-readableinstructions that, when executed, e.g., by the processor 80, cause theIMD 16 and/or the control module 81 to perform various functionsattributed to the IMD 16 and/or the control module 81 described herein.Further, the memory 82 may include any volatile, non-volatile, magnetic,optical, and/or electrical media, such as a random access memory (RAM),read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasableprogrammable ROM (EEPROM), flash memory, and/or any other digital media.An exemplary capture management module may be the left ventricularcapture management (LVCM) module described in U.S. Pat. No. 7,684,863entitled “LV THRESHOLD MEASUREMENT AND CAPTURE MANAGEMENT” and issuedMar. 23, 2010, which is incorporated herein by reference in itsentirety.

The processor 80 of the control module 81 may include any one or more ofa microprocessor, a controller, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field-programmablegate array (FPGA), and/or equivalent discrete or integrated logiccircuitry. In some examples, the processor 80 may include multiplecomponents, such as any combination of one or more microprocessors, oneor more controllers, one or more DSPs, one or more ASICs, and/or one ormore FPGAs, as well as other discrete or integrated logic circuitry. Thefunctions attributed to the processor 80 herein may be embodied assoftware, firmware, hardware, or any combination thereof.

The control module 81 may be used to determine the effectiveness of theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 using theexemplary methods and/or processes described herein according to aselected one or more programs, which may be stored in the memory 82.Further, the control module 81 may control the therapy delivery module84 to deliver therapy (e.g., electrical stimulation therapy such aspacing) to the heart 12 according to a selected one or more therapyprograms, which may be stored in the memory 82. More, specifically, thecontrol module 81 (e.g., the processor 80) may control variousparameters of the electrical stimulus delivered by the therapy deliverymodule 84 such as, e.g., AV delays, pacing pulses with the amplitudes,pulse widths, frequency, or electrode polarities, etc., which may bespecified by one or more selected therapy programs (e.g., AV delayadjustment programs, pacing therapy programs, pacing recovery programs,capture management programs, etc.). As shown, the therapy deliverymodule 84 is electrically coupled to electrodes 40, 42, 44, 45, 46, 47,48, 50, 58, 62, 64, 66, e.g., via conductors of the respective lead 18,20, 22, or, in the case of housing electrode 58, via an electricalconductor disposed within housing 60 of IMD 16. Therapy delivery module84 may be configured to generate and deliver electrical stimulationtherapy such as pacing therapy to the heart 12 using one or more of theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66.

For example, therapy delivery module 84 may deliver pacing stimulus(e.g., pacing pulses) via ring electrodes 40, 44, 45, 46, 47, 48 coupledto leads 18, 20, and 22, respectively, and/or helical tip electrodes 42and 50 of leads 18 and 22. Further, for example, therapy delivery module84 may deliver defibrillation shocks to heart 12 via at least two ofelectrodes 58, 62, 64, 66. In some examples, therapy delivery module 84may be configured to deliver pacing, cardioversion, or defibrillationstimulation in the form of electrical pulses. In other examples, therapydelivery module 84 may be configured deliver one or more of these typesof stimulation in the form of other signals, such as sine waves, squarewaves, and/or other substantially continuous time signals.

The IMD 16 may further include a switch module 85 and the control module81 (e.g., the processor 80) may use the switch module 85 to select,e.g., via a data/address bus, which of the available electrodes are usedto deliver therapy such as pacing pulses for pacing therapy, or which ofthe available electrodes are used for sensing. The switch module 85 mayinclude a switch array, switch matrix, multiplexer, or any other type ofswitching device suitable to selectively couple the sensing module 86and/or the therapy delivery module 84 to one or more selectedelectrodes. More specifically, the therapy delivery module 84 mayinclude a plurality of pacing output circuits. Each pacing outputcircuit of the plurality of pacing output circuits may be selectivelycoupled, e.g., using the switch module 85, to one or more of theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 (e.g., a pairof electrodes for delivery of therapy to a pacing vector). In otherwords, each electrode can be selectively coupled to one of the pacingoutput circuits of the therapy delivery module using the switchingmodule 85.

The sensing module 86 is coupled (e.g., electrically coupled) to sensingapparatus, which may include, among additional sensing apparatus, theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 to monitorelectrical activity of the heart 12, e.g., electrocardiogram(ECG)/electrogram (EGM) signals, etc. The ECG/EGM signals may be used tomeasure or monitor activation times (e.g., ventricular activationstimes, etc.), heart rate (HR), heart rate variability (HRV), heart rateturbulence (HRT), deceleration/acceleration capacity, decelerationsequence incidence, T-wave alternans (TWA), P-wave to P-wave intervals(also referred to as the P-P intervals or A-A intervals), R-wave toR-wave intervals (also referred to as the R-R intervals or V-Vintervals), P-wave to QRS complex intervals (also referred to as the P-Rintervals, A-V intervals, or P-Q intervals), QRS-complex morphology, STsegment (i.e., the segment that connects the QRS complex and theT-wave), T-wave changes, QT intervals, electrical vectors, etc.

The switch module 85 may be also be used with the sensing module 86 toselect which of the available electrodes are used, or enabled, to, e.g.,sense electrical activity of the patient's heart (e.g., one or moreelectrical vectors of the patient's heart using any combination of theelectrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66). Likewise,the switch module 85 may be also be used with the sensing module 86 toselect which of the available electrodes are not to be used (e.g.,disabled) to, e.g., sense electrical activity of the patient's heart(e.g., one or more electrical vectors of the patient's heart using anycombination of the electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62,64, 66), etc. In some examples, the control module 81 may select theelectrodes that function as sensing electrodes via the switch modulewithin the sensing module 86, e.g., by providing signals via adata/address bus.

In some examples, sensing module 86 includes a channel that includes anamplifier with a relatively wider pass band than the R-wave or P-waveamplifiers. Signals from the selected sensing electrodes may be providedto a multiplexer, and thereafter converted to multi-bit digital signalsby an analog-to-digital converter for storage in memory 82, e.g., as anelectrogram (EGM). In some examples, the storage of such EGMs in memory82 may be under the control of a direct memory access circuit.

In some examples, the control module 81 may operate as an interruptdriven device, and may be responsive to interrupts from pacer timing andcontrol module, where the interrupts may correspond to the occurrencesof sensed P-waves and R-waves and the generation of cardiac pacingpulses. Any necessary mathematical calculations may be performed by theprocessor 80 and any updating of the values or intervals controlled bythe pacer timing and control module may take place following suchinterrupts. A portion of memory 82 may be configured as a plurality ofrecirculating buffers, capable of holding one or more series of measuredintervals, which may be analyzed by, e.g., the processor 80 in responseto the occurrence of a pace or sense interrupt to determine whether thepatient's heart 12 is presently exhibiting atrial or ventriculartachyarrhythmia.

The telemetry module 88 of the control module 81 may include anysuitable hardware, firmware, software, or any combination thereof forcommunicating with another device, such as a programmer. For example,under the control of the processor 80, the telemetry module 88 mayreceive downlink telemetry from and send uplink telemetry to aprogrammer with the aid of an antenna, which may be internal and/orexternal. The processor 80 may provide the data to be uplinked to aprogrammer and the control signals for the telemetry circuit within thetelemetry module 88, e.g., via an address/data bus. In some examples,the telemetry module 88 may provide received data to the processor 80via a multiplexer.

The various components of the IMD 16 are further coupled to a powersource 90, which may include a rechargeable or non-rechargeable battery.A non-rechargeable battery may be selected to last for several years,while a rechargeable battery may be inductively charged from an externaldevice, e.g., on a daily or weekly basis.

FIG. 17B is another embodiment of a functional block diagram for IMD 16.FIG. 17B depicts bipolar RA lead 22, bipolar RV lead 18, and bipolar LVCS lead 20 without the LA CS pace/sense electrodes and coupled with animplantable pulse generator (IPG) circuit 31 having programmable modesand parameters of a bi-ventricular DDD/R type known in the pacing art.In turn, the sensor signal processing circuit 91 indirectly couples tothe timing circuit 83 and via data and control bus to microcomputercircuitry 33. The IPG circuit 31 is illustrated in a functional blockdiagram divided generally into a microcomputer circuit 33 and a pacingcircuit 21. The pacing circuit 21 includes the digital controller/timercircuit 83, the output amplifiers circuit 51, the sense amplifierscircuit 55, the RF telemetry transceiver 41, the activity sensor circuit35 as well as a number of other circuits and components described below.

Crystal oscillator circuit 89 provides the basic timing clock for thepacing circuit 21, while battery 29 provides power. Power-on-resetcircuit 87 responds to initial connection of the circuit to the batteryfor defining an initial operating condition and similarly, resets theoperative state of the device in response to detection of a low batterycondition. Reference mode circuit 37 generates stable voltage referenceand currents for the analog circuits within the pacing circuit 21, whileanalog to digital converter ADC and multiplexer circuit 39 digitizesanalog signals and voltage to provide real time telemetry if a cardiacsignals from sense amplifiers 55, for uplink transmission via RFtransmitter and receiver circuit 41. Voltage reference and bias circuit37, ADC and multiplexer 39, power-on-reset circuit 87 and crystaloscillator circuit 89 may correspond to any of those presently used incurrent marketed implantable cardiac pacemakers.

If the IPG is programmed to a rate responsive mode, the signals outputby one or more physiologic sensor are employed as a rate controlparameter (RCP) to derive a physiologic escape interval. For example,the escape interval is adjusted proportionally to the patient's activitylevel developed in the patient activity sensor (PAS) circuit 35 in thedepicted, exemplary IPG circuit 31. The patient activity sensor 27 iscoupled to the IPG housing and may take the form of a piezoelectriccrystal transducer as is well known in the art and its output signal isprocessed and used as the RCP. Sensor 27 generates electrical signals inresponse to sensed physical activity that are processed by activitycircuit 35 and provided to digital controller/timer circuit 83. Activitycircuit 35 and associated sensor 27 may correspond to the circuitrydisclosed in U.S. Pat. No. 5,052,388 entitled “METHOD AND APPARATUS FORIMPLEMENTING ACTIVITY SENSING IN A PULSE GENERATOR” and issued on Oct.1, 1991 and U.S. Pat. No. 4,428,378 entitled “RATE ADAPTIVE PACER” andissued on Jan. 31, 1984, each of which are incorporated herein byreference in their entireties. Similarly, the exemplary systems,apparatus, and methods described herein may be practiced in conjunctionwith alternate types of sensors such as oxygenation sensors, pressuresensors, pH sensors and respiration sensors, all well known for use inproviding rate responsive pacing capabilities. Alternately, QT time maybe used as the rate indicating parameter, in which case no extra sensoris required. Similarly, the exemplary embodiments described herein mayalso be practiced in non-rate responsive pacemakers.

Data transmission to and from the external programmer is accomplished byway of the telemetry antenna 57 and an associated RF transceiver 41,which serves both to demodulate received downlink telemetry and totransmit uplink telemetry. Uplink telemetry capabilities will typicallyinclude the ability to transmit stored digital information, e.g.operating modes and parameters, EGM histograms, and other events, aswell as real time EGMs of atrial and/or ventricular electrical activityand marker channel pulses indicating the occurrence of sensed and paceddepolarizations in the atrium and ventricle, as are well known in thepacing art.

Microcomputer 33 contains a microprocessor 80 and associated systemclock and on-processor RAM and ROM chips 82A and 82B, respectively. Inaddition, microcomputer circuit 33 includes a separate RAM/ROM chip 82Cto provide additional memory capacity. Microprocessor 80 normallyoperates in a reduced power consumption mode and is interrupt driven.Microprocessor 80 is awakened in response to defined interrupt events,which may include A-TRIG, RV-TRIG, LV-TRIG signals generated by timersin digital timer/controller circuit 83 and A-EVENT, RV-EVENT, andLV-EVENT signals generated by sense amplifiers circuit 55, among others.The specific values of the intervals and delays timed out by digitalcontroller/timer circuit 83 are controlled by the microcomputer circuit33 by way of data and control bus from programmed-in parameter valuesand operating modes. In addition, if programmed to operate as a rateresponsive pacemaker, a timed interrupt, e.g., every cycle or every twoseconds, may be provided in order to allow the microprocessor to analyzethe activity sensor data and update the basic A-A, V-A, or V-V escapeinterval, as applicable. In addition, the microprocessor 80 may alsoserve to define variable, operative AV delay intervals and the energydelivered to each ventricle.

In one embodiment, microprocessor 80 is a custom microprocessor adaptedto fetch and execute instructions stored in RAM/ROM unit 82 in aconventional manner. It is contemplated, however, that otherimplementations may be suitable to practice the present invention. Forexample, an off-the-shelf, commercially available microprocessor ormicrocontroller, or custom application-specific, hardwired logic, orstate-machine type circuit may perform the functions of microprocessor80.

Digital controller/timer circuit 83 operates under the general controlof the microcomputer 33 to control timing and other functions within thepacing circuit 320 and includes a set of timing and associated logiccircuits of which certain ones pertinent to the present invention aredepicted. The depicted timing circuits include URI/LRI timers 83A, V-Vdelay timer 83B, intrinsic interval timers 83C for timing elapsedV-EVENT to V-EVENT intervals or V-EVENT to A-EVENT intervals or the V-Vconduction interval, escape interval timers 83D for timing A-A, V-A,and/or V-V pacing escape intervals, an AV delay interval timer 83E fortiming the A-LVp delay (or A-RVp delay) from a preceding A-EVENT orA-TRIG, a post-ventricular timer 83F for timing post-ventricular timeperiods, and a date/time clock 83G.

The AV delay interval timer 83E is loaded with an appropriate delayinterval for one ventricular chamber (e.g., either an A-RVp delay or anA-LVp delay as determined using known methods) to time-out starting froma preceding A-PACE or A-EVENT. The interval timer 83E triggers pacingstimulus delivery, and can be based on one or more prior cardiac cycles(or from a data set empirically derived for a given patient).

The post-event timer 83F time out the post-ventricular time periodfollowing an RV-EVENT or LV-EVENT or a RV-TRIG or LV-TRIG andpost-atrial time periods following an A-EVENT or A-TRIG. The durationsof the post-event time periods may also be selected as programmableparameters stored in the microcomputer 33. The post-ventricular timeperiods include the PVARP, a post-atrial ventricular blanking period(PAVBP), a ventricular blanking period (VBP), a post-ventricular atrialblanking period (PVARP) and a ventricular refractory period (VRP)although other periods can be suitably defined depending, at least inpart, on the operative circuitry employed in the pacing engine. Thepost-atrial time periods include an atrial refractory period (ARP)during which an A-EVENT is ignored for the purpose of resetting any AVdelay, and an atrial blanking period (ABP) during which atrial sensingis disabled. It should be noted that the starting of the post-atrialtime periods and the AV delays can be commenced substantiallysimultaneously with the start or end of each A-EVENT or A-TRIG or, inthe latter case, upon the end of the A-PACE which may follow the A-TRIG.Similarly, the starting of the post-ventricular time periods and the V-Aescape interval can be commenced substantially simultaneously with thestart or end of the V-EVENT or V-TRIG or, in the latter case, upon theend of the V-PACE which may follow the V-TRIG. The microprocessor 80also optionally calculates AV delays, post-ventricular time periods, andpost-atrial time periods that vary with the sensor based escape intervalestablished in response to the RCP(s) and/or with the intrinsic atrialrate.

The output amplifiers circuit 51 contains a RA pace pulse generator (anda LA pace pulse generator if LA pacing is provided), a RV pace pulsegenerator, and a LV pace pulse generator or corresponding to any ofthose presently employed in commercially marketed cardiac pacemakersproviding atrial and ventricular pacing. In order to trigger generationof an RV-PACE or LV-PACE pulse, digital controller/timer circuit 83generates the RV-TRIG signal at the time-out of the A-RVp delay (in thecase of RV pre-excitation) or the LV-TRIG at the time-out of the A-LVpdelay (in the case of LV pre-excitation) provided by AV delay intervaltimer 83E (or the V-V delay timer 83B). Similarly, digitalcontroller/timer circuit 83 generates an RA-TRIG signal that triggersoutput of an RA-PACE pulse (or an LA-TRIG signal that triggers output ofan LA-PACE pulse, if provided) at the end of the V-A escape intervaltimed by escape interval timers 83D.

The output amplifiers circuit 51 includes switching circuits forcoupling selected pace electrode pairs from among the lead conductorsand the IND_CAN electrode 20 to the RA pace pulse generator (and LA pacepulse generator if provided), RV pace pulse generator and LV pace pulsegenerator. Pace/sense electrode pair selection and control circuit 53selects lead conductors and associated pace electrode pairs to becoupled with the atrial and ventricular output amplifiers within outputamplifiers circuit 51 for accomplishing RA, LA, RV and LV pacing.

The sense amplifiers circuit 55 contains sense amplifiers correspondingto any of those presently employed in contemporary cardiac pacemakersfor atrial and ventricular pacing and sensing. High impedance P-wave andR-wave sense amplifiers may be used to amplify a voltage differencesignal that is generated across the sense electrode pairs by the passageof cardiac depolarization wavefronts. The high impedance senseamplifiers use high gain to amplify the low amplitude signals and relyon pass band filters, time domain filtering and amplitude thresholdcomparison to discriminate a P-wave or R-wave from background electricalnoise. Digital controller/timer circuit 83 controls sensitivity settingsof the atrial and ventricular sense amplifiers 55.

The sense amplifiers are typically uncoupled from the sense electrodesduring the blanking periods before, during, and after delivery of a pacepulse to any of the pace electrodes of the pacing system to avoidsaturation of the sense amplifiers. The sense amplifiers circuit 55includes blanking circuits for uncoupling the selected pairs of the leadconductors and the IND-CAN electrode 20 from the inputs of the RA senseamplifier (and LA sense amplifier if provided), RV sense amplifier andLV sense amplifier during the ABP, PVABP and VBP. The sense amplifierscircuit 55 also includes switching circuits for coupling selected senseelectrode lead conductors and the IND-CAN electrode 20 to the RA senseamplifier (and LA sense amplifier if provided), RV sense amplifier andLV sense amplifier. Again, sense electrode selection and control circuit53 selects conductors and associated sense electrode pairs to be coupledwith the atrial and ventricular sense amplifiers within the outputamplifiers circuit 51 and sense amplifiers circuit 55 for accomplishingRA, LA, RV and LV sensing along desired unipolar and bipolar sensingvectors.

Right atrial depolarizations or P-waves in the RA-SENSE signal that aresensed by the RA sense amplifier result in a RA-EVENT signal that iscommunicated to the digital controller/timer circuit 83. Similarly, leftatrial depolarizations or P-waves in the LA-SENSE signal that are sensedby the LA sense amplifier, if provided, result in a LA-EVENT signal thatis communicated to the digital controller/timer circuit 83. Ventriculardepolarizations or R-waves in the RV-SENSE signal are sensed by aventricular sense amplifier result in an RV-EVENT signal that iscommunicated to the digital controller/timer circuit 83. Similarly,ventricular depolarizations or R-waves in the LV-SENSE signal are sensedby a ventricular sense amplifier result in an LV-EVENT signal that iscommunicated to the digital controller/timer circuit 83. The RV-EVENT,LV-EVENT, and RA-EVENT, LA-SENSE signals may be refractory ornon-refractory, and can inadvertently be triggered by electrical noisesignals or aberrantly conducted depolarization waves rather than trueR-waves or P-waves.

The techniques described in this disclosure, including those attributedto the IMD 16, the computing apparatus 140, and/or various constituentcomponents, may be implemented, at least in part, in hardware, software,firmware, or any combination thereof. For example, various aspects ofthe techniques may be implemented within one or more processors,including one or more microprocessors, DSPs, ASICs, FPGAs, or any otherequivalent integrated or discrete logic circuitry, as well as anycombinations of such components, embodied in programmers, such asphysician or patient programmers, stimulators, image processing devices,or other devices. The term “module,” “processor,” or “processingcircuitry” may generally refer to any of the foregoing logic circuitry,alone or in combination with other logic circuitry, or any otherequivalent circuitry.

Such hardware, software, and/or firmware may be implemented within thesame device or within separate devices to support the various operationsand functions described in this disclosure. In addition, any of thedescribed units, modules, or components may be implemented together orseparately as discrete but interoperable logic devices. Depiction ofdifferent features as modules or units is intended to highlightdifferent functional aspects and does not necessarily imply that suchmodules or units must be realized by separate hardware or softwarecomponents. Rather, functionality associated with one or more modules orunits may be performed by separate hardware or software components, orintegrated within common or separate hardware or software components.

When implemented in software, the functionality ascribed to the systems,devices and techniques described in this disclosure may be embodied asinstructions on a computer-readable medium such as RAM, ROM, NVRAM,EEPROM, FLASH memory, magnetic data storage media, optical data storagemedia, or the like. The instructions may be executed by one or moreprocessors to support one or more aspects of the functionality describedin this disclosure.

This disclosure has been provided with reference to illustrativeembodiments and is not meant to be construed in a limiting sense. Asdescribed previously, one skilled in the art will recognize that othervarious illustrative applications may use the techniques as describedherein to take advantage of the beneficial characteristics of theapparatus and methods described herein. Various modifications of theillustrative embodiments, as well as additional embodiments of thedisclosure, will be apparent upon reference to this description.

What is claimed is:
 1. A system for assisting in noninvasive locationselection for an implantable electrode comprising: electrode apparatuscomprising a plurality of external electrodes configured to be locatedproximate tissue of a patient; imaging apparatus configured to image atleast a portion of blood vessel anatomy of the patient's heart; adisplay apparatus comprising a graphical user interface, wherein thegraphical user interface is configured to depict the at least a portionof blood vessel anatomy of the patient's heart; and computing apparatuscoupled to the electrode apparatus, imaging apparatus, and displayapparatus and configured to provide the graphical user interfacedisplayed on the display apparatus to assist a user in noninvasivelyselecting a location for an implantable electrode, wherein the computingapparatus is further configured to: display, on the graphical userinterface, at least a portion of blood vessel anatomy of the patient'sheart, measure mechanical motion of the at least a portion of bloodvessel anatomy of the patient's heart using the imaging apparatus,display, on the graphical user interface, mechanical motion informationof one or more regions of the at least a portion of blood vessel anatomyof the patient's heart based on the measured mechanical motion, identifya region of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart, measure surrogate electricalactivation time using one or more external electrodes of the pluralityof external electrodes of the electrode apparatus proximate theidentified region of the at least a portion of blood vessel anatomy ofthe patient's heart, and display, on the graphical user interface, themeasured surrogate activation time for the identified region of the atleast a portion of blood vessel anatomy of the patient's heart.
 2. Thesystem of claim 1, wherein, to measure surrogate electrical activationtime using one or more external electrodes of the plurality of externalelectrodes of the electrode apparatus proximate the identified region ofthe at least a portion of blood vessel anatomy of the patient's heart,the computing apparatus is further configured to: identify positions ofthe plurality of external electrodes with respect to the identifiedregion of the at least a portion of blood vessel anatomy of thepatient's heart using the imaging apparatus; and measure surrogateelectrical activation time using the one or more external electrodes ofthe plurality of external electrodes of the electrode apparatus that areclosest to the identified region of the at least a portion of bloodvessel anatomy of the patient's heart.
 3. The system of claim 2, whereinthe computing apparatus is further configured to display, on thegraphical user interface, graphical representations of positionsassociated with the plurality of external electrodes with respect to theat least a portion of blood vessel anatomy of the patient's heart. 4.The system of claim 1, wherein the plurality of external electrodes areconfigured to be positioned proximate tissue of the patient by a user,wherein each external electrode of the plurality of external electrodesis positionable proximate a different specific area of the patient thanthe other external electrodes of the plurality of external electrodes,wherein each different specific area corresponds to a different regionof the patient's heart, wherein, to measure surrogate electricalactivation time using one or more external electrodes of the pluralityof external electrodes of the electrode apparatus proximate theidentified region of the at least a portion of blood vessel anatomy ofthe patient's heart, the computing apparatus is further configured tomeasure surrogate electrical activation time using the one or moreexternal electrodes of the plurality of electrodes of the electrodeapparatus that correspond to the identified region of the at least aportion of blood vessel anatomy of the patient's heart.
 5. The system ofclaim 1, wherein, to identify a region of the one or more regions of theat least a portion of blood vessel anatomy of the patient's heart, thecomputing apparatus is further configured to allow a user to select theregion of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart using the graphical userinterface.
 6. The system of claim 1, wherein the at least a portion ofblood vessel anatomy of the patient's heart comprises at least a portionof the coronary sinus.
 7. The system of claim 1, wherein, to displaymechanical motion information of the at least a portion of blood vesselanatomy of the patient's heart, the computing apparatus is furtherconfigured to color scale the at least a portion of blood vessel anatomyof the patient's heart on the graphical user interface according to themeasured mechanical motion.
 8. The system of claim 1, wherein, todisplay the measured surrogate activation time for the identified regionof the one or more regions of the at least a portion of blood vesselanatomy of the patient's heart, the computing apparatus is furtherconfigured to alphanumerically depict the measured surrogate activationtime proximate the identified region of the one or more regions of theat least a portion of blood vessel anatomy of the patient's heart on thegraphical user interface.
 9. The system of claim 1, wherein the at leasta portion of blood vessel anatomy of the patient's heart displayed onthe graphical user interface is a three-dimensional graphicalrepresentation.
 10. The system of claim 1, wherein the plurality ofexternal electrodes comprises surface electrodes positioned in an arrayconfigured to be located proximate the skin of the patient.
 11. Thesystem of claim 1, wherein the graphical user interface displayed on thedisplay apparatus is configured to assist a user in noninvasivelyselecting an implant location for at least one implantable electrodecoupled to at least one lead.
 12. The system of claim 1, wherein thecomputing apparatus is further configured to display, on the graphicaluser interface, scar information for the identified region of the one ormore regions of the at least a portion of blood vessel anatomy of thepatient's heart indicating a likelihood of the identified regioncomprising scar tissue.
 13. A method for assisting in noninvasivelocation selection for an implantable electrode comprising: displayingon a graphical user interface at least a portion of blood vessel anatomyof a patient's heart; measuring mechanical motion of the at least aportion of blood vessel anatomy of the patient's heart using imagingapparatus; displaying on the graphical user interface mechanical motioninformation of one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart based on the measured mechanicalmotion; identifying a region of the one or more regions of the at leasta portion of blood vessel anatomy of the patient's heart; measuringsurrogate electrical activation time using one or more externalelectrodes proximate the identified region of the one or more regions ofthe at least a portion of blood vessel anatomy of the patient's heart,wherein the one or more external electrodes are located proximate tissueof a patient; displaying on the graphical user interface the measuredsurrogate activation time for the identified region of the one or moreregions of the at least a portion of blood vessel anatomy of thepatient's heart; and navigating at least one implantable electrode tothe identified region of the one or more regions of the at least aportion of blood vessel anatomy of the patients heart using thegraphical user interface.
 14. The method of claim 13, wherein measuringsurrogate electrical activation time using one or more externalelectrodes proximate the identified region of the one or more regions ofthe at least a portion of blood vessel anatomy of the patient's heartcomprises: identifying positions of a plurality of external electrodeswith respect to the identified region of the one or more regions of theat least a portion of blood vessel anatomy of the patient's heart usingthe imaging apparatus; and measuring surrogate electrical activationtime using the one or more external electrodes of the plurality ofexternal electrodes that are closest to the identified region of the oneor more regions of the at least a portion of blood vessel anatomy of thepatient's heart.
 15. The method of claim 14, wherein measuring surrogateelectrical activation time using one or more external electrodesproximate the identified region of the one or more regions of the atleast a portion of blood vessel anatomy of the patient's heart furthercomprises displaying on the graphical user interface graphicalrepresentations of the positions associated with the plurality ofexternal electrodes with respect to the at least a portion of bloodvessel anatomy of the patient's heart.
 16. The method of claim 13,wherein measuring surrogate electrical activation time using one or moreexternal electrodes proximate the identified region of the one or moreregions of the at least a portion of blood vessel anatomy of thepatient's heart comprises: positioning a plurality of externalelectrodes proximate tissue of the patient, wherein each externalelectrode of the plurality of external electrodes is positionedproximate a different specific area of the patient than the otherexternal electrodes of the plurality of external electrodes, whereineach different specific area corresponds to a different region of thepatient's heart; and measuring surrogate electrical activation timeusing the one or more external electrodes of the plurality of externalelectrodes that correspond to the identified region of the one or moreregions of the at least a portion of blood vessel anatomy of thepatient's heart.
 17. The method of claim 13, wherein identifying aregion of the one or more regions of the at least a portion of bloodvessel anatomy of the patient's heart comprises allowing a user toselect the region of the one or more regions of the at least a portionof blood vessel anatomy of the patient's heart using the graphical userinterface.
 18. The method of claim 13, wherein the at least a portion ofblood vessel anatomy of the patient's heart comprises at least a portionof the coronary sinus.
 19. The method of claim 13, wherein displayingmechanical motion information of the at least a portion of blood vesselanatomy of the patient's heart comprises color scaling the at least aportion of blood vessel anatomy of the patient's heart on the graphicaluser interface according to the measured mechanical motion.
 20. Themethod of claim 13, wherein displaying the measured surrogate activationtime for the identified region of the one or more regions of the atleast a portion of blood vessel anatomy of the patient's heart comprisesalphanumerically depicting the measured surrogate activation timeproximate the identified region of the one or more regions of the atleast a portion of blood vessel anatomy of the patient's heart on thegraphical user interface.
 21. The method of claim 13, wherein the atleast a portion of blood vessel anatomy of the patient's heart displayedon the graphical user interface is a three-dimensional graphicalrepresentation.
 22. The method of claim 13, wherein the one or moreexternal electrodes comprise surface electrodes positioned in an arrayconfigured to be located proximate the skin of the patient.
 23. Themethod of claim 13, wherein the method further comprises displaying, onthe graphical user interface, scar information for the identified regionof the one or more regions of the at least a portion of blood vesselanatomy of the patient's heart indicating a likelihood of the identifiedregion comprising scar tissue.
 24. A system for assisting in noninvasivelocation selection for an implantable electrode comprising: a displayapparatus comprising a graphical user interface, wherein the graphicaluser interface is configured to depict at least a portion of bloodvessel anatomy of the patient's heart; and computing apparatus coupledto the display apparatus and configured to provide the graphical userinterface displayed on the display apparatus to assist a user innoninvasively selecting a location for an implantable electrode, whereinthe computing apparatus is further configured to: display, on thegraphical user interface, at least a portion of blood vessel anatomy ofthe patient's heart, display, on the graphical user interface,mechanical motion information of one or more regions of the at least aportion of blood vessel anatomy of the patient's heart, and display, onthe graphical user interface, a measured surrogate activation time foran identified region of the one or more regions of the at least aportion of blood vessel anatomy of the patient's heart.
 25. A method forassisting in noninvasive location selection for an implantable electrodecomprising: displaying on a graphical user interface at least a portionof blood vessel anatomy of a patient's heart; displaying on thegraphical user interface mechanical motion information of one or moreregions of the at least a portion of blood vessel anatomy of thepatient's heart; and displaying on the graphical user interface ameasured surrogate activation time for an identified region of the oneor more regions of the at least a portion of blood vessel anatomy of thepatient's heart